A Critical Review of Theories and Research


Lysergic Acid Diethylamide (LSD)


Mental Health

 By David Abrahart

March 1998

Submitted as part fulfillment of the requirements for the award of Master of Arts degree in Mental Health Studies at the University of Portsmouth.



Chapter 1 Flashbacks

Chapter 2 Psychoses

Chapter 3 Therapeutic Uses

Conclusions and Recommendations

Personal comments






This introduction will demonstrate the contemporary relevance of a re-evaluation of research concerning LSD and its effects on mental health. It outlines the objectives and methods used for this dissertation. The research is located within its social-political context and the historical suppression of social uses of psychedelic substances. Relevant changes in psychiatry and research methodologies are discussed, and the major confounding variable of pharmaceutical purity of LSD is elaborated.

The relevance of this study for Mental Health practice.

The influence of evidenced-based practice in mental health is growing, particularly in it's challenge to orthodox beliefs and practices. This dissertation will examine the research concerning the orthodox beliefs that LSD use has adverse consequences with no therapeutic use.

In my professional capacity as a mental health social worker I am frequently involved with individuals who have used LSD, in addition to working with their relatives or carers. It is important that I have a full appreciation of the true risk, underpinned by research, and can give reliable information and support to both. The use of LSD is heavily stigmatised and misunderstood within the field of mental health, and has become grouped with a range of other street drugs as yet another drug of abuse. This is reinforced by the worldwide prohibition of the substance.

This is particularly relevant now since research in the United States has recorded a rise in the use of hallucinogenic drugs between 1991 and 1996, rising from 6% to 14% (Hunts, 1997). Also recently in the United States the Food and Drugs Administration has now authorised research on human subjects (Yensen and Dryer, 1995) after a gap of almost 30 years, and the therapeutic potential may yet be established.

With the rise in the use of hallucinogenics, the recommencement of medically supervised human experiments and the accumulation of a widespread and established literature relating to LSD, it seems pertinent to re-examine these beliefs and re-evaluate the research carried out todate.


The outcome of this dissertation will be a thorough and academically rigorous evaluation of the research concerning positive and negative effects of LSD in relation to the mental health of the person using it, as well as an evaluation of its effectiveness in treatment. Consequently this dissertation will attempt to answer the following questions:

To what extent does the research literature and theory substantiate that:

        1. a relationship exists between LSD and flashbacks?
        2. LSD precipitates a psychosis?
        3. LSD is an important aid in psychotherapy?
        4. LSD is an aid in working with alcoholism?


To meet this dissertation's objectives the author adopted a literature research methodology suggested by Cormack (1984) and Dempsey & Dempsey (1986) to enable an extensive, thorough and systematic examination of the relevant publications.

This review comprised two separate stages:

Firstly, the author endeavored to locate as many important publications on the topic as was feasible within the constraints detailed below. This established what had been published in the field, when and by whom. The author particularly aimed to discover recent publications, which would summarise and critique earlier work, or report contemporary research, and provide bibliographies for further research.

Using the search keywords of 'LSD', 'flashbacks', 'drug-induced psychosis', 'substance abuse' and 'psychedelic', the author obtained printouts of searches from the CD-ROM bibliographic data bases of MedLine 1983 -1997, PsycLit 1974 -1997, Guardian Newspaper 1992-96, Independent Newspaper 1992-96 and the Times and Sunday Times 1992-96. 

Similarly the author searched the University of Portsmouth's library database for books on the subject using the same keywords.

Since the material is several decades old, published predominately between the period 1950s to 1970s, much is available on the Internet. The author used the search engines Yahoo (http://www.yahoo.com) and Altavista, (http://www.altavista.com) using 'LSD' as a keyword, which produced an enormous number of sites to explore. However it quickly became clear that there are a small number of key large sites on the Internet containing information about LSD. For example, The Lyceaum (http://www.lyceaum.org), Hyperreal (http://www.hyperreal.org), Schaffer Library (http://druglibrary.org) and Multidisciplinary Association for Psychedelic Studies (http://www.maps.org) .

In particular the MAPS site has two large downloadable bibliographies, the Sandoz Bibliography and MedLine searchable database for the period from 1961. This site proved particularly valuable, as the author was able to search the bibliographic abstracts from the journals for relevance. Similarly the MAPS discussion forum was a source of up to date information and book reviews. All of the Internet sites have documents, books, forums or searchable databases, which were particularly helpful.

 Secondly, having identified the range of literature, the next step was to produce a critical review of those publications, which were particularly significant to the topics in question.

The author's aim consequently moved from identifying secondary sources to primary ones. The author took secondary sources (such as literature reviews) to be reviews and reanalysis of previous publications which gave an overview and insight into the particular areas. In particular the author identified two such secondary sources, which were useful in finding primary sources. For adverse effects the author used Strassman's (1984) review, which was not only large in its survey and scope, but also used strict methodological criteria which the published research had to meet to be included. For therapeutic effects the author used Passie's (1997) bibliography as a guide.

In particular the author looked for publications based on research, rather than philosophical speculations, with an identified research methodology to substantiate the results obtained, since these could be critiqued, as opposed to straightforward claims of success without such controls.

Using a combination of the abstracts, in conjunction with the discussion in these texts, the author identified primary texts and research and perused their bibliographies for others. The author used primary texts to overcome any errors or bias that could have crept into the secondary sources.

One piece of information the author has been unable to obtain is that concerning the claim for compensation by psychiatric patients who were given LSD by psychiatrists in the 1950s-60s, reported in the Guardian in 1995. This would have helped present a user perspective to contrast with the dominant medical perspective used in this dissertation.

The publications identified were obtained as journal reprints through the library service, as were any books likewise identified. Not all primary material could be obtained, either because of its unavailability, time or financial constraints. However the author believes that a representative selection was obtained.

The literature obtained was organised within a personal computer database. This allowed the easy itemisation of each publication, notes on their main features and relevance. In addition, its sort and print features allowed easy manipulation of the data, the production of a bibliography and the management of the large amount of data accumulated.

Socio-political Context

Since this dissertation concentrates on LSD's therapeutic use in psychotherapy and in the treatment of alcoholism, and considers 'flashbacks' and 'LSD psychoses' as adverse mental health consequences, it is relevant to place these ideas in the social-political context in which they arose. This can be dated to the late 50s to early 70s, and involve an interplay of historical, cultural and psychiatric influences, particularly in the United States.

Grob (1994) describes the historical suppression of psychedelic substances in Western societies, previously on religious grounds, and argues that their continued suppression is simply a continuation of this process, albeit now based on medical grounds. Such substances began to be re-discovered in the late 1880s, but generally did not enter into the public domain until the early 60s. Consequently some authors, like Jensen (1994), place the use of LSD within the long cultural history of the shamanic use of botanical hallucinogens for healing purposes, which dates back to prehistoric times (8000 BC). Thus the claims of adverse reactions are cultural artifacts arising from a society which prohibits such substances and experiences.

Grob (1994) records that whilst LSD was used as a treatment in psychiatry from the mid 50s, the medical establishment was divided in its' opinion about LSD. For some it was an important treatment aid, or facilitated an expansion in consciousness. For others LSD produced avoidable psychoses and irrationality amongst its advocates. This argument raged during the 60s producing a rift in the medical establishment. A major conflict encountered by some of the researchers, such as Leary (1964) was that their desire to produce religious or mystical experiences corresponded to shamanic ideas, and consequently engendered hostile or incredulous reactions from the medical establishment, which was profoundly biochemically orientated. However those who argued against the use of LSD because of adverse effects won the day.

Reports of 'flashbacks' and 'LSD psychosis' featured strongly in the media at that time. Stevens (1988) in his history of LSD and American culture describes how 'flashbacks' became part of the anti-drug propaganda and anti-LSD hysteria of the mid-60s, where it quickly became an exaggerated journalistic staple diet. He argues that 'some researchers never encountered them, others saw them everywhere, and others dismissed them as no big deal'. Similarly he traces the origins of the 'LSD psychotic' back to sensationalised reporting without factual basis by the media. He shows that the actual evidence was dubious, generated by misunderstandings and the deliberate ignoring of any real incidence of actual psychosis.

Grob (1994) writes that the interest in hallucinogens had catalysed, and was catalysed by, the profound cultural shifts of the 60s. They had a central role in a movement, the counterculture, that began to question many of the basic values and precepts of mainstream Western culture. The promotion of the 'illumination of the mind' coincided with the mass protest movements in Western industrialised nations against the existing social norms and values.

For example, Leary and Alpret (1962) write:

'Make no mistake, the effect of consciousness expanding drugs will be to transform our concepts of human nature, of human potentialities, of existence.........these possibilities naturally threaten every branch of the establishment......'

Baggott (1997) writes that the health concerns of some of the medical establishment were meet by Governmental concerns about social control and suppression of the drug movement, creating a climate for the prohibition of all aspects of LSD use. The reports of bad trips, adverse effects, chromosome damage and the imprisonment of the LSD revolutionaries, such as Kesey and Leary (1964), created a retreat by the psychiatrists away from the therapeutic use of LSD and its eventual prohibition.

Consequently it can be seen that the social-political context influenced and generated the ideas of flashbacks, LSD induced psychoses and that LSD had no therapeutic use. This dissertation will re-evaluate the research literature to see if these claims have validity outside of the social context of their origin.

Pharmaceutical purity

Whilst this dissertation concentrates on the effects of a specific substance, LSD, the research discussed may be compromised by an uncertainty about the substance used, its strength and dose. Whilst medically supervised LSD use would have used pharmaceutically pure LSD, this is generally not the case for the research into adverse effects. Since LSD use was prohibited in 1966 (in the United States), most of research on adverse effects involved individuals who had obtained LSD on the black market, whose real composition, purity and strength would be unknown.

The synthesis of LSD is a difficult procedure, and Eisner (1977) records the decline in quality of 'street' LSD since 1968. He argues that the experience of pharmaceutically pure LSD had a 'spiritual dimension' which is now missing. Current 'street' LSD is neither 'the passionate flame' nor 'the life giving sun'.

Henderson and Glass (1994) review investigations of street drugs in the United States. In 1970 14 of 15 samples were LSD and in 1973, of 405 samples 92% contained LSD. However other research described by Siva Sankar (1975) found that of 515 samples, 44% contained LSD with two or more contaminants, or were mixtures of intermediate chemicals resulting from a failed synthesis of LSD.

In addition to concerns about pharmaceutical purity, individual street doses also varied, both in strength, and from changes in recreational use over time.

Such strength is also a function of the decomposition of LSD when exposed to light and oxygen. Henderson and Glass (1994) write that both improper storage will quickly reduce in potency, and also that it is produced in forms, such as soaked blotting paper, which are almost designed to accelerate its breakdown within weeks or months.

Henderson and Glass (1994) report that in the United States, street dosages were between 200-250 micrograms in the 60s, but by the mid 70s, this ranged between 50-300 micrograms. This average dose reduced in the mid 80s to between 100-125 micrograms, and by the 1990s ranged between 20-80 micrograms. This reduction in strength is reflected in the change in LSD's recreational use from the deeper personal explorations off the 60s to the more hedonistic use of the 1990s, where the smaller dose gives individuals a psychedelic experience but still allows the user some element of control.

Consequently a major confounding variable is introduced into the research. Arguments relying purely on the degree of exposure to 'street' LSD clearly must be considered unreliable. Research carried out in the 60s would encounter individuals using dosage levels quite differently from those in the 90s.

Changes in Psychiatry and Research Practices

By using only medical research sources, this dissertation is limited to research within the medical profession within the social context of the1950 -1970s. In examining this research, it is important to contextualise this in the generally accepted research methodologies valid during that period. Grob (1994) writes that the world of psychiatry has changed substantially in the 30 years since LSD research was halted. At that time psychoanalytic approaches were dominant, with an emphasis on case studies. Psychoanalysis has now receded to relative obscurity as psychiatry has become progressively dominated by adherents of biological reductionism, with its preference for rigorous methodology and research design.

Consequently whilst the value of claims of success within contemporary psychiatry can no longer rest on such case studies and anecdotes, the research considered here, particularly those concerning psychotherapeutic use of LSD, does use such case studies. Similarly the discussion on adverse effects, particularly those relating to prolonged psychoses, is dominated by such case studies.

Prospective research designs, those that measure change using before and after measurements are therefore poorly represented, and post prohibition, could be thought as unethical if the detection of adverse effects was the prime research intention. However it is surprising that considering the number of psychiatric patients who were given pure LSD, that no follow up research was carried out (bar McGlothlin and Arnold's (1971) unrepresentative study discussed below).


This dissertation will now critically re-evaluate the research on 'flashbacks' and 'LSD psychosis' in Chapters 1 and 2 respectively and 'therapeutic use' in psychotherapy and alcoholism in Chapter 3.


Chapter One



 "The man who comes back through the Door in the Wall will never be quite the same as the man who went out"

Aldous Huxley

The Doors of Perception, 1954


This chapter will discuss the research literature on flashbacks as an adverse effect of LSD use, in terms of their definition, incidence and explain the research findings using theoretical approaches from the literature.

 The Literature on Flashbacks

This chapter is based on 31 articles and is totally derived from medical journals. Most of these articles are now dated, the latter ones being reviews of the former. Whilst published books contain small resumes about flashbacks, these either suggest one explanatory model or are intended to serve as a warning to LSD users by their inclusion in a discussion of 'adverse effects' (cf. Henderson and Glass, 1994). Whilst giving a cross-section of opinion and research, they leave the reader with no firm idea of what the research shows.

What are flashbacks?

Perhaps the major problem in considering whether flashbacks are an adverse effect of LSD use is whether they are an actual phenomenon, since the majority (see below) of LSD users claim not to have experienced them! In the medical literature they are taken to be an established fact. Eisner and Cohen (1958) first reported the spontaneous reoccurrence of LSD phenomena, described by their inpatients as 'relaxing and beneficial'. These reoccurrences have now become established as 'flashbacks' or 'Hallucinogen Persisting Perceptual Disorder' (American Psychological Association, 1997). They have been defined as transient, spontaneous reoccurrences of psychedelic drug effects following a period of normalcy after a psychedelic drug experience (Wesson and Smith, 1976). Shick and Smith (1970) write that the period of normality following the psychedelic experience distinguishes flashbacks from other consequences (discussed in Chapter 2) thought to be continuous with the drug experience, such as psychoses.

The form 'flashbacks' are said to take has also been researched and quantified in the medical literature. Horowitz (1969) describes flashbacks as being commonly visual, although they can take any form. However Shick and Smith (1970) write that flashbacks can embrace all the senses and be perceptual, somatic or emotional in nature. Matefy et al (1978) researched this using paid student volunteers (n = 63) attracted by campus adverts, and has quantified the most commonly reported flashbacks into categories according to the frequency with which they were reported. These are shown in Table 1:



Flashback Type

% frequency

Perceptual distortions




Anxiety, tension or panic


Disorientation or confusion


Union with the world


Bodily sensations


Auditory hallucinations


Visual hallucinations


Unconscious thought


Feeling of depression




Adapted from Matefy (1978)

However, others remain critical of research based on subjective reports of 'flashbacks' from individuals. McGlothlin and Arnold (1971) write that:

'........... it is important to stress that the evidence generally allows one to conclude only that a spontaneous experience, subjectively described as LSD-like, followed the use of the drug - not that it was caused by such use….In very few instances does there appear to be substantial evidence of a causal relationship between the LSD experience and the incidents described. In the large majority of cases, there seems to be nothing more than the association of two events bearing certain similarities". (page 46)

Does anyone have them?

There is a bias in the medical literature towards reporting evidence of and determining incidence of 'flashbacks' as adverse effects. This is evident from the manner in which results are expressed in terms of stating how many individuals have flashbacks rather than how many do not, which has to be inferred by the reader. For example published estimates of the prevalence of flashbacks range from 15% (McGlothlin and Arnold, 1971) to 77% (Holsten 1976) of LSD users. This can also be read as saying that between 23-85% of users do not experience flashbacks, which could throw doubt on a direct causal relationship between LSD use and flashbacks. Other factor(s) must be involved. In examining these figures, the substantial difference in estimates of incidence needs to be explained.

Stanton and Bardoni (1972) argue that the frequency of reported flashbacks from a 'normal' population differs from those from a 'psychiatric' population. Their own research within a military population shows that of 240 declared users of LSD, 22.9% said they had experienced flashbacks. This is very similar to figures obtained from other researchers investigating non-psychiatric populations (Table 2). If these results are summed together, an average reported rate of incidence of flashbacks of 23% is found amongst normal populations of LSD users.

However, Stanton and Bardoni's research can be questioned in that whilst they carried out an anonymous questionnaire to enlisted males under 25 years of age in Vietnam, they left the respondent to define 'flashback' for themselves. This personal definition is clearly unsatisfactory and does not enable comparisons between studies, nor does it allow for an examination of the nature of such 'flashback' reports. Consequently a major variable was not controlled for or quantified.

Naditch and Fenwick (1977) also researched for evidence of flashbacks, using an anonymous questionnaire to respondents identified by chain referrals. The subjects (n = 235) were young males, with a mean age of 21.2 (S.D. 2.6). Whilst 28% of the respondents replied that they had experienced flashbacks, it is interesting to note that in other areas (see below) the researchers did not believe other answers that were also given.

Horowitz (1969) interviewed a smaller sample (n = 31) of individuals said to be representative members of a drug-taking community, found that 32% (that is 8 individuals) reported having flashbacks. However there was poly-drug use amongst this group, which could have confounded the results.

Taken together (Table 2) the research results if summated could mean that 77% of LSD users in non-psychiatric sample populations do not report experiencing flashbacks.





Sample Size

% Flashbacks





Owens et al








Stanton & Bardoni




Naditch & Fenwick









Henderson and Glass (1994) write that there is a higher incidence (55-65%) of reports of flashbacks from research using psychiatric populations (Table 3). Holsten (1976) has the highest reported incidence. This is a study of 65 young drug users. Fifty of the 60 had flashbacks after using LSD, and those with flashbacks had overall the worst clinical and social outcomes.

Abraham's (1983) study is also a questionnaire given to 70 male subjects, of 23 years mean age who were referred to him by doctors. Subjects were psychiatric outpatients. 53.5% reported flashbacks. Abraham himself outlines the problems of reliability of self-reports, dosage, and other confounding variables, such as intelligence, personality and pre-existing psychopathology.

McGlothlin and Arnold's (1971) study actually reports the lowest incidence of reported flashbacks, at 15%. The sample population (n = 247) included 124 individuals who had been given LSD in conjunction with psychotherapy, and 123 individuals involved in experimental research. 58 had extra-medical use of LSD. The study was a follow-up of patients almost 10 years later. However the sample population was not a representative selection of either a 'normal' or 'psychiatric' population. The average age at interview was 44, 54% had a degree, and also included artists and intellectuals.







Sample Size


Robbins et al




McGlothlin and Arnold



15%, mixture of clients

Holsten, F









Leaving aside McGlothlin and Arnold's 1971 study as unrepresentative of either a normal or psychiatric population, how can the elevated levels of reports of flashbacks in psychiatric patients be explained? This might be explained in at least two ways:

a) that only individuals who 'complain' about their symptoms (= flashbacks) come to the notice of psychiatrists, and thus skew the figures. Wesson and Smith (1976) argue that since most studies of flashbacks are based on case reports of individuals seeking help from doctors, they do not offer evidence of incidence of flashbacks in the 'normal' population. Of course the converse can be argued that not all individuals who are having adverse flashbacks seek help from doctors. The figures could be higher still. Shick and Smith (1970) argue that only those who suffer anxiety as a consequence of their flashbacks would seek help.

b) that individuals who are predisposed to psychopathology and hence psychiatric care, have more flashbacks than those who are not because of the nature of their psychiatric problems.

Consequently evidence of incidence from research based on a psychiatric population is bound to be skewed towards more serious pathology. Whilst there is some consensus by researchers of 'normal' populations of an incidence of approximately 23%, there are still some methodological problems in defining what flashbacks are. However nearly all research substantiates that that only a minority (23%) of LSD users from a 'normal' population will report experiencing flashbacks. Assuming these reports are accurate, they suggest that LSD use per se does not cause flashbacks. There has to be another phenomenon involved, which may be linked to the use of LSD.


Pleasant and Unpleasant Flashbacks.

To be considered adverse, a flashback must be experienced as undesirable, which is clearly a subjective opinion of the individual concerned. Two studies, Naditch and Fenwick (1977) and Matefy and Krall (1975) have researched this (Table 4) and show similar results.



Naditch & Fenwick (1977)

Matefy & Krall (1974)

Very pleasant


Always pleasant


Moderately pleasant


Usually pleasant


Half and Half


Moderately frightening


Usually unpleasant


Very frightening


Always unpleasant




Rosenthal (1964) suggests that an important difference between pleasant and unpleasant flashbacks appears to involve the element of voluntary control. He writes that the pleasant sensations are 'semi-voluntary' in the sense that the subject can make them more or less intense to the extent that he concentrates on them. He gives an example where light breaks up into droplets of shimmering colour, shimmering panels of colour before the patient's eyes and brightly coloured shape distortions. However he offers no research evidence to support this. Naditch and Fenwick (1977) however are not convinced that the 57% of individuals researched who said they enjoyed their flashbacks really did. They describe those individuals as exhibiting 'la belle indifference' in a manner suggesting a hysterical conversion.

Matefy and Krall (1974) report that 63% of users in their research group thought they had no control over their flashbacks, although 55% did not find them unpleasant.


Rosenthal (1964) writes that flashbacks, which are deemed frightening, are those which are involuntary. These can include hallucinations of cats, crabs, insects, corpses and skulls. Horowitz's (1969) depiction of flashbacks as "repeated intrusions of frightening images in spite of volitional attempts to avoid them" found no corroboration in McGlothlin and Arnold's (1971) atypical research population. However from Table 4 between 43-45% of reported flashbacks are described as unpleasant to very frightening.

Research summation

Research has therefore demonstrated that only 23% of LSD users in normal populations report flashbacks, of which between 42%-45% are regarded as unpleasant. Thus less than 10% of LSD users report unpleasant flashbacks. Psychiatric populations report higher rates. However it remains to be established if there are any causal links between flashbacks and LSD use.

Explanatory Theories of Flashbacks

In view of the above discussion, any explanatory theory of flashbacks must explain why:

      1. approximately 77% of users claim never to have experienced flashbacks;
      2. a higher proportion of 'psychiatric' patients report flashbacks than 'normal' populations; and
      3. there is a link with LSD use.

The theoretical explanations of flashbacks in the literature can be divided into four general approaches according to basic premises. Of course the explanations given are not necessarily mutually exclusive:

  1. Explanations based on a pre-existing disposition to psychopathology;

A pre-existing disposition to psychopathology might explain the excess of flashbacks within psychiatric populations. It may also account for those individuals with flashbacks in 'normal' populations as well if they could be considered to have more minor pathologies. Robbins et al (1967) postulated this 'Latent Psychotic Theory', that those who experience flashbacks are so predisposed and that the use of LSD precipitates that pathology. However he has become misquoted in the literature on flashbacks. His article clearly shows he was referring to psychotic reactions not flashbacks.

However a bias can be detected in researchers' personal opinions of drug users, which could influence their reporting of 'psychopathologies'. As Poole and Brabbins (1996) write, the world of the drug culture is alien to psychiatrists' personal experience. Cohen (1969), described as representing 'responsible science' (Novak, 1997), clearly demonstrates this bias, in the guise of a clinical diagnosis, when he describes frequent users of LSD as 'emotionally inadequate and immature …unable to cope with the massive stress of a dissociative experience'. They are 'borderline' individuals '…who sense an invisible partition between themselves and other people'. Similarly hedonists are deprecated as 'incapable of everyday enjoyment and requiring supramaximal stimulation to …feel alive'. Thus a confounding variable is introduced into the reporting of this research where 'psychopathology' may be confused with a difference in lifestyle.

Smart and Jones (1970) researched psychopathology within LSD users experiencing flashbacks. They studied 100 paid volunteers from informal sources who used LSD. The sample was predominantly male (over 80%), with an age spread of 15-37 (mean 22.5 years). The majority of these individuals had taken other drugs in addition to LSD. It could not be determined how representative of the LSD using community these volunteers were. A control group of college students was used. Using the Minnesota Multiphasic Personality Inventory (MMPI) they discovered that 96% of the LSD user group had abnormal profiles. They showed far greater psychological disturbances than the control group, much of which pre-dated LSD use. 51% had mental health problems in the past, as opposed to 17.4% of the controls. They found the LSD group to be 'impulsive, marginally adjusted and non-conformist, with a history of underachievement and easy morals'. However the study is ambiguous in its lack of a representative sample population and the substantial confounding variable of polydrug use.

If those who use LSD have more psychopathologies, do those who experience flashbacks have even more? Matefy and Krall (1974) argue that LSD users who experience flashbacks should evidence more psychopathological symptoms on the MMPI than those users who do not. They tested this theory by using the MMPI with two groups of LSD users, one group experiencing flashbacks and the other group not experiencing flashbacks. These were college students, paid participants (n = 22). The researchers found that those who reported having flashbacks did not report more behaviours and attitudes indicative of general psychopathology than the other group. However they did have a tendency towards a higher score on the 'paranoid' scale. This would indicate that they might be more suspicious, feel persecuted or tend to be overly sensitive to a greater extent than those who did not have flashbacks. However the statistical validity of results derived from such a small sample population can be questioned.

Again Matefy and Krall (1975) researched a group of 58 users, 28 having flashbacks and 30 who did not, using the MMPI, and found that whilst those who had flashbacks had a tendency toward hysterical behaviour under stress, they did not show more psychotic characteristics.

Consequently in the literature there is little support for psychopathology as being the cause of flashbacks, although a bias of deprecation of substance users has been identified. However there is evidence that individuals who use LSD may have more psychopathologies, although the representativeness of that sample populations can be challenged. As Matefy and Krall (1974) argue, it is always tempting to explain psychological processes that are not understood as somehow a manifestation of 'mental illness' or some psychological deficit. This has not been supported by research.


  1. Psychodynamic explanations.

Several approaches theorise from a psychodynamic perspective, either on the resemblance of flashbacks to conversion symptoms, or that flashbacks are unresolved conflicts from gestalts activated by the psychedelic session, or that the effect of a dominant defence mechanism exacerbates the effect of LSD.

Horowitz (1969) argues that within psychodynamic theory flashbacks are thought to be conversion reactions, where defensive functions of the ego are incapable of completely repressing memories or conflicts stimulated or exacerbated by the psychedelic experience. Flashbacks are the symptoms of this process. He writes that 'in some flashbacks the imagery content seems to be a symbolic depiction of an affect state or situational crisis (e.g. despair and hopelessness) ….. seem to be ..traumatic perceptions ….from the experience that were overwhelmingly frightening at the time they were hallucinated. When the trauma is worked through … the flashbacks cease.'

Saidel and Babineau (1976) argue that the literature reports that 'schizoid' and 'obsessive' personalities are vulnerable to prolonged flashbacks. (Cf. Zeidenberg 1973). They hypothesise that anxiety sets off a complex physiological and psychological reaction that leads somehow to a return of symptoms. They conceptualise flashbacks as falling somewhere between a conversion symptom and a symptom of a traumatic neurosis. Using a case study to highlight their argument, they show that the need for control, orderliness and predictability for such people is shattered by the upsurge of images and affect during a psychedelic experience. The flashback is seen as an adaptable symptom. In their example of a 'socially phobic obsessive' it was apparently a process of substituting his ruminations about his perceptual distortions for his previous ruminations. Symptom relief occurred concurrent with his significant resolution of a developmental crisis, which his symptoms had inhibited by fostering a clinging and nurturing relationship with his girlfriend, a replacement for his mother who he feared was disowning him.


In a similar vein, Grof (1994) writes that the adverse effects of LSD reflect deep, basic dynamics of unconscious processes. If unconscious gestalts activated during the psychedelic experience remain incompleted, they lead to an intensification of symptoms and so-called adverse reactions. This follows from the weakening of the person's defence system. Whilst this material is covered up by defensive mechanisms which have remained strong enough to cover up the activated but unresolved material, this is only true on the surface, resulting in a precarious dynamic balance between the unconscious forces and the psychological resistance to them. Any number of circumstances can upset this balance resulting in a flashback. The individual perceives this as a belated effect of the drug rather than a continuation of the process activated in the psychedelic session

Naditch and Fenwick (1977) argue that personality factors, involving the dominant psychological defence mechanisms of the individual and the reasons why the individual chose to use LSD, may be predisposing factors for the generation of flashbacks. They researched 235 LSD users, from a sample of 483 male drug users contacted through a system of chain referrals. They administered an anonymous questionnaire and found however that with the exception of the use of repression, differences in ego functioning did not make independent contributions to the development of flashbacks.

A psychodynamic approach may explain why only a few individuals who use LSD subsequently report flashbacks, and also the higher reports from within psychiatric populations. The use of LSD could be seen as either an activator of unconscious processes or alternatively the effects of a psychedelic experience interact with defence mechanisms in ways that produce 'flashbacks'.

Perhaps the most important critique of psychodynamic approaches is that these arguments cannot be falsified; that is they cannot be tested in such a way to disprove them. Psychodynamic approaches consequently remain hypothetical.


3) Physiological approaches.

These approaches theorise that a build up of LSD or its effects causes flashbacks, or that flashbacks are dose dependent. Smart and Bateman (1967) argue that LSD use and its effects build up over time. Under certain circumstances, such as stressful events, this manifests itself in the form of flashbacks. However these ideas are very dated and have been overtaken by research. Shick and Smith (1970) write that since the half life of LSD in plasma has been found to be 175 minutes, such views are untenable, particularly when the wide variation of differences in onset and duration of flashbacks are considered.

Others consider the relationship between the extent of LSD use and flashbacks. In reviewing the literature, Henderson and Glass (1994) write that some studies show a relationship between the extent of use of LSD and flashbacks, whereas others do not. The (corrected) studies they quote are set out below in Table 5, which includes details to aid discussion of the results. However discussion here will be limited to those studies which are based on research with large sample populations. As identified above, a major confounding variable for such research is determining the dose of LSD actually taken by the individual given the wide range of strengths in street LSD and its propensity to decompose quickly.

McGlothlin and Arnold (1971) report a positive relationship between the extent of drug use and flashbacks. Their research population was untypical (see above) with the lowest reported incidence of flashbacks. They found that 19% and 13% respectively of non-medical and medical use individuals reported flashbacks, with those who had taken LSD more than ten times were twice as likely to report flashbacks than those did with less exposure to LSD.

Abraham (1983) also found a positive relationship, using a research sample of 70 psychiatric outpatients. By plotting lifetime dosage against dependent variables of visual disturbances, a non-linear relationship between dose, flashbacks and response was found. This had a peak at 15 exposures, another at 40 exposures, then a plateau afterwards. He argues that this may show a three way genetic susceptibility to differing exposures to LSD. However the mean exposure to LSD was 96 exposures which may undermine confidence in assessing variance at the lower end of minimal LSD usage. Similarly other confounding variables in this study (described above) throw some doubt on the reliability of this study.

Stanton and Bardoni (1972) researched a 'normal' military population, and in endeavouring to determine comparable results with McGlothlin and Arnold's (1971) study, similarly based their analyses on exposures segmented into groups of ten, and also into different segments. They did not find a relationship between frequency of use and flashbacks. Shick and Smith (1970) write that flashbacks have been reported after just one dose, which would seem to undermine arguments based on level of exposure to LSD.











Yes - research suggests a non-linear relationship between dose, flashbacks and response, with a peak at 15 exposures, then at 40 exposures, then a plateau afterwards.



Yes - military recruits (N=422) However questionnaire was not anonymous, drug use not systematically identified and personality factors not reported.



No (N=31) - no statistical difference between high and low drug users

Matefy et al


No (N=63) - research found no evidence for this

McGlothlin and Arnold


Yes They found that individuals with ten or more LSD sessions were twice as likely to report flashbacks than those who had had less than ten such sessions.



Yes - but based on a literature review; he presents only one case study of a woman who had had previous dissociative states. Quotes Cooper (1955) who states, but does not offer data, that hallucinations and related adverse effects are noted after repeated heavy doses.

Shick and Smith


Yes. However their arguments are based on two case studies, and are otherwise generally ambiguous on this point.

Smart and Bateman



Stanton & Bardoni


No (N=240) - no correlation between extent of LSD use and flashbacks


Consequently research demonstrating a link between flashbacks and extent of LSD use has methodological difficulties and atypical research populations. Within normal populations no such evidence seems to have been demonstrated. Shick and Smith's (1970) counterexample ('a single exposure') seems to disprove any such relationship. Finally all rely on the notion of a causal link between LSD use and flashbacks, which has not been adequately demonstrated.

Consequently explanatory approaches within a physiological approach are either scientifically outdated, falsified by research or the research itself may be considered methodologically unreliable.


4) Non-pathological approaches.

 These approaches center on the idea that flashbacks can be explained without resorting to notions of psychopathology or unconscious, unseen processes. These theories involve individuals' suggestibility, selective attention to naturally occurring perception phenomena or that flashbacks involve an element of social role play with attendant reinforcing benefits to the individual.

Heaton (1975) argues that if an individual expects to have a flashback, in appropriate circumstances this expectation can give rise to the apparent experience of flashbacks. Heaton argues that 'psychedelic' experiences do not appear to differ qualitatively from Altered States of Consciousness (ASCs) which can be achieved by a variety of procedures and naturally occurring circumstances not involving drug use. Flashbacks are found to occur in some settings or circumstances that induce ASCs in the absence of previous psychedelic drug use, e.g. reduced sensory input, stress, fatigue or extreme relaxation. Therefore those who experience flashbacks are mislabeling or selectively attending to aspects of naturally occurring perceptions which are reminiscent of the psychedelic experience. Wesson and Smith (1976) call this a 'sensitisation theory'. Once an individual notices phenomena during a psychedelic experience, any reoccurrence of those sensations is interpreted as a reoccurrence of the psychedelic state. If this is perceived as being negative, this 'flashback' may generate fear and anxiety, leading to a circular process escalating the fear to panic.

Heaton (1975) researched this using two groups of 16 individuals recruited through clinics and counselling agencies, one group's members had flashbacks; the other did not. The subjective experiences in identical settings were found to be altered by giving the subjects instructions to expect flashbacks. If they were told to expect flashbacks they did so, irrespective of whether they had had previous flashbacks or not. Consequently he argues that if a psychedelic user enjoys or fears recurrent psychedelic sensations and/or is a member of a subculture which emphasises them, it is quite possible that the individual will expect to experience flashbacks. That is, the individual will selectively attend to relevant aspects of naturally occurring ASCs and mislabel them as flashbacks. Consequently whilst the psychedelic experience has given the individual an awareness of phenomena usually inhibited, the phenomena themselves are not pathological and are not caused by the use of LSD.

Wesson and Smith (1976) have also called this a 'self fulfilling prophecy' approach. Such 'adverse' reactions could be generated by the negative publicity given to LSD by the media, doctors and psychiatrists which brings about an expectation of such bad reactions. For example Braden (1971) writes of his own experiences having been told by a 'formidable' psychiatrist that all LSD use engenders brain damage and the anxiety he subsequently suffered. He argues that his experience lends credence to the hypothesis that the press and the medical profession between them have contributed by continually emphasising the dangers and negative aspects of the psychedelic experience.

Matefy et al (1978) questioned their research group about whether they expected continuing reactions from their use of LSD. 77% did expect to have such reactions. However if this is the case it does not explain why 77% of LSD users do not experience flashbacks, unless they have no awareness of either the adverse publicity or that flashbacks are a possibility. Matefy's group clearly knew about flashbacks, which seems to discount this possibility.

Matefy (1973,74,75,78,79) offers a theory of flashbacks from a behavioural viewpoint. Using an analogy with hypnosis studies, he argues that it is possible under appropriate circumstances to produce somatic or psychological effects of drugs without having taken them. He argues that through repeated use of LSD, a person learns expectations appropriate in the drug high situation, and they propose that the individual is able to simulate a drug trip by re-enacting the role demands of a drugged individual.

They outline a case study when an individual's flashbacks became a conditioned response to social situations, which the individual found difficult. They describe how these behaviours, shaped through the LSD experience, were moulded into a consistent pattern through reinforcements derived from avoiding stressful events. They show how the individual gained sympathy from significant individuals through 'flashbacks'.

To substantiate this theory, Matefy (1980) researched this with a group of 87 paid volunteers. 34 had flashbacks, 29 did not and 24 were non drug-using controls. If the theory is correct then those individuals who have flashbacks should have a greater propensity for deep engrossment in role-playing activities, which results in altered feelings and perceptions congruent with that role. They found that such individuals scored highly on the experience inventory in regard to role taking, suggestibility and vividness of imagery.

A number of theories identify non-pathological learning processes as being the cause of flashbacks. LSD has been theorised as a non-causal agent in these processes, although it has shown the individual phenomena usually inhibited. The research demonstrates that expectancy is a factor in the formation of flashbacks, but does not seem to adequately explain why 77% of individuals do not have flashbacks. It would be ironic if media and medical concerns about adverse effects resulting from the use of LSD actually generate the adverse reactions they warn against !



As an adverse effect of the use of LSD, research suggests that flashbacks have a very tenuous relationship with the chemical itself. Not only do most users claim not to have flashbacks, but also less than 10% of those who do report flashbacks report them as being unpleasant. The explanatory models used to explain them rely on individual characteristics, such as suggestibility, role play and the noticing of naturally occurring phenomena which had previously been disregarded, rather than suggesting a pathology. Indeed it could be argued that even the activating of unconscious material can be seen in a favourable light, as the individual can begin working with it.


Chapter Two



 "……. and everywhere the diagnosis is the same: psychotic illness resulting from the unauthorised, non-medical use of LSD"

TIME Magazine, March 1966



This Chapter will review the research evidence that LSD can cause a prolonged psychosis in those who use it. Similarly the nature of this psychosis will be examined, particularly with reference to Schizophrenia. Research that it precipitates Schizophrenia earlier in those predisposed will be examined and alternative arguments concerning substance use for self-medication explored.


The Concern

One of the dangers attributed to the use of LSD is it's ability to cause a prolonged psychosis in healthy individuals or to hasten the onset of such a psychosis in those predisposed to them. To validate the claim that LSD can produce a psychosis, it would need to be demonstrated in the research literature. Strassman (1984) argues that to establish any casual links between LSD use and psychosis, prospective studies should be employed so that a methodologically sound comparison of before and after could be achieved. However the literature is somewhat sparse on such research, and usually compares groups of LSD users with non-users to establish differences in causation.

The legal constraints on such studies are now prohibitive since the use of LSD has been banned. Since the use of LSD happens illicitly in unofficial unsupervised settings, the researchers can only use individuals who are presented to them as having problems. This poses an unavoidable constraint on any research methodology and may consequently increase reliance on reports of individual case studies.

The literature for both qualitative and quantitative evidence for prolonged psychoses following LSD use comprises mostly of small case studies or literature reviews of such studies. The author has only been able to find three studies (Table 6) which have researched the incidence of 'prolonged psychoses' following the use of LSD in medical or experimental settings involving medical supervision. Cohen (1960) and Malleson (1971) carried out research studies based on questionnaire surveys of medical professionals who were using LSD in their treatments. Only McGlothlin's (1967) study was prospective in design and researched the effects of the administration of LSD to college graduates.

















A third of professionals surveyed failed to reply





College students. No schizophrenic reactions reported



4300 patients

170 experi-mental


9 per 1000 prolonged psychoses


Cohen (1960) sent questionnaires to 62 American researchers and received 44 replies. He assembled data on 5000 psychiatric patients and experimental subjects administered LSD or mescaline, amounting to over 25,000 doses. He found that there were only five reports of a prolonged psychotic reaction, although the figure would be too small to reliably be separated into different rates for psychiatric patients and normal individuals. Malleson (1971) surveyed all the researchers using LSD in the United Kingdom in 1968. He gathered data on 4300 psychiatric patients, who between them received 49,5000 doses of LSD. Prolonged psychoses were reported in 37 patients. McGlothlin's prospective study of 155 college students reported no prolonged psychoses.

Averaging from Cohen and Malleson's figures, albeit from psychiatric populations, a rate of 4 per 1000 individuals can be established for incidence of a prolonged psychosis. McGlothlin's (1967) report of no prolonged psychoses is more difficult to interpret. The sample would be too small to draw conclusions from, bearing in mind the average incidence established from Cohen and Malleson's studies.

Taylor and Warner (1994) offer a critique of Cohen (1960) and Malleson (1971) figures. They argue that all the long lasting reactions in Cohen's study occurred in psychiatric patients, and are not strikingly higher than the generally accepted incidence of Schizophrenia (0.5 per 1000) in the general population. Similarly Malleson's figure of 37 cases (although Taylor and Warner (1994) only use the figure of 10, the most prolonged of the reported psychoses) again occurred in psychiatric patients. They argue that whilst this is a higher figure than might be expected in the general population, in such a 'high risk' group this is to be expected. Consequently they argue that any evidence for 'prolonged psychoses' to be drawn from this research is equivocal at best.

Whilst the literature contains numerous case studies of individuals allegedly 'normal' before taking LSD and later psychotic, these reports cannot be quantified. For example Abbruzi (1975) writes several case studies where 'well-balanced normal individuals' experience prolonged psychoses after taking LSD. There are similar studies by Robbins (1967), Glass and Bowers (1970), and Bowers (1977).

Consequently it is difficult to draw conclusions as to how frequent such reactions may be, in addition to trying to establish causation without experimental rigour. However the case studies identified above do seem to suggest that there may be a relationship between LSD use and a 'prolonged psychosis'. Prospective research has been suggested as an appropriate methodology for this research but cannot be accomplished. Reliance on case studies does not present quantitative evidence, but perhaps suggests that there may be a link.

Is it schizophrenia or an LSD psychosis?

Warner and Taylor (1994) have suggested that reports of prolonged psychoses may actually be reports of the normal incidence of psychosis within the general population, and the use of LSD is co-incidental. This could be established if the psychoses following LSD use was somehow different from other psychoses arising from mental illnesses, such as Schizophrenia.

However the research is confounded by a poor definition of a 'drug induced psychosis' and the confusion caused by using Schizophrenics in control groups. Poole and Brabbins (1996) argue that psychiatry has no consistent definition of a 'drug-induced psychosis', and that the relationship between drug use and psychiatric symptoms is controversial. They write that the literature on this subject as a whole is marked by an inference of a causal relationship, which is not supported by the data upon which it is based. The studies are methodologically unsound, and do not explore drug use as it occurs in the 'real world'. They argue that this stems from the lack of personal experience of psychiatrists in the drug subculture.

A problem with using Schizophrenics as controls is that this seems to assume that any psychoses caused by the use of LSD is comparable to Schizophrenia, rather than constituting a distinct syndrome, that of a toxic psychosis. Young (1974) has reviewed this literature and has identified a pattern whereby some researchers try to show that LSD produces a psychotic state and equally others try to show that it does not. His own research comparing experiences of matched samples of LSD users, hospitalised schizophrenics and controls to identify similarities was inconclusive. However whilst there were more similarities than differences, there were also similarities in certain respects with the control group. Several significant differences were identified between LSD users and Schizophrenics experiences, primarily in the affective nature of their experiences and also the presence of delusions in some Schizophrenic states. This is in agreement with Langs and Barr (1968) who demonstrate that neither the LSD state nor the Schizophrenic state are uniform syndromes, and are best conceptualised as a syndrome-complex within which a variety of symptom pictures may be found.

Hollister (1962) argues that these drug-induced psychoses can be differentiated from Schizophrenia. He argues that because both states have symptoms in common, researchers have termed such drug-like reactions as 'schizophrenic-like', which by force of authority and repetition has been continued in the literature. He argues from his own research that no single symptom or set of symptoms will distinguish schizophrenia from other mental states, but rather an entire set delineates the syndrome. He concludes that the presenting symptoms of withdrawal, delusions of reference, thought disorders, belief in the hallucinations and delusions differ between the groups. Such reactions differ in total between the groups.

Vardy and Kay (1983), on the other hand, argue that in most respects LSD psychotics were fundamentally similar to Schizophrenics in genealogy, phenomenology and course of illness. They argue their findings support a model of LSD psychosis as a drug-induced schizophreniform reaction in persons vulnerable to both substance use and psychosis. They conclude that, judged according to the contemporary DSM 2 criteria for a schizophreniform disorder (i.e. Schizophrenia of less than six months duration), symptoms were similar to both groups. There were differences in incidence of delusions, thought disorders and depressive traits (LSD 30.8%, 25%, 34.6% and Schizophrenia 70.6%, 47%, 11.8% respectively). They did find a much higher level of parental alcoholism in the LSD user group than that of parents of Schizophrenics. Despite this somewhat large disparity, they continue to argue that an LSD psychosis is not a nosological entity distinct from acute Schizophrenia, or attributable to toxic drug effects.

Bowers and Freedman (1966) attempted by research and review to show that individuals' subjective reports of schizophrenia and psychedelic experiences are very similar. They argue that the debate has concentrated on clinical data rather then subjective experience, and gives a false impression of dissimilarity between the two states. From seven case studies of schizophrenics, the individuals involved reported subjective experiences of:

1. heightened perceptual modes and singularly intense emotional responses;

  1. experiences felt like a breakthrough or release, using words like release and creativity;
  2. feelings of getting to the essence of things;
  3. stepping beyond restrictions of usual states of awareness.

These were accompanied however by a vague, disquieting, progressive sense of dread, which may eventually predominate their experience. They argue that since LSD induces comparable perceptual and affective conditions, psychedelic and psychotic phenomena are closely related. Separating psychedelic states as being different from psychotic states has conferred a false status onto psychedelic states.

Consequently the literature reflects a difference of opinion as to whether the prolonged psychosis is the same as or is different from Schizophrenia. The research evidence suggests that there are differences when the psychosis is seen as a whole syndrome when compared with schizophrenic syndromes. The literature then is ambiguous about whether these prolonged psychoses are related specifically to LSD (that is an LSD psychosis) or to an occurrence of Schizophrenia.


Can LSD use precipitate Schizophrenia earlier ?

If the prolonged psychosis is in fact Schizophrenia, can LSD use precipitate it's onset earlier than would have otherwise been predicted? To determine this would require that there is a particular age at which Schizophrenia starts. This is not confirmed in the literature. Gregory (1987) writes that whilst the onset of Schizophrenia is usually in adolescence or early adult life, it may also develop in childhood or be delayed until middle-age or later still. This is confirmed by the American Psychological Association (1987). However Eysenck (1972) writes that the mean age of onset is in the range between 25-35 years. Thus the age at which Schizophrenia starts has a wide age range with a gradual onset. Therefore the research would have to demonstrate that a psychosis would not normally have happened if the person had not taken LSD in the absence of a specific age of onset. This would be difficult to demonstrate. Consequently the research is focused on comparisons of age differences between groups of Schizophrenics who used LSD and those who did not.

Taylor and Warner (1994) argue that if LSD does provoke an earlier onset of an inevitable illness (Schizophrenia) it should be demonstrable in that it would advance the onset of psychoses in LSD using patients. They argue that the age of onset of psychosis should therefore be earlier in subjects whose illness is preceded by LSD use. To test this, they carried out research using 59 schizophrenic outpatients with long-standing illnesses. Whilst they found that most subjects with Schizophrenia and schizoaffective disorder used illicit substances before the onset of illness, those who did not fell ill 2.6 years earlier than those who had used drugs before the onset of illness. They argue that allowance must be made in research for age related effects. When their sample is divided into cohorts of subjects of similar age, 5 or 10 years apart, within any age cohort the age of onset of illness is later (not earlier) among those who used substances before the onset of illness. The older patients had not had the opportunity of exposure to substances that is now available for the younger people.

On the other hand, Breakey et al (1974) argue from their research that LSD use precipitates the illness earlier than otherwise would have happened in people predisposed to Schizophrenia. They compared a group of Schizophrenics who used LSD (n=26) with a group (n=14) who had not. They found that those who had used LSD had a four-year earlier onset of symptoms than those who had not. They also were said to have better premorbid personalities than those who had not used LSD. However the substance users mostly used more than one drug (median of 4) which clearly confounds data purely concerned with LSD. Similarly the standard deviation for age of onset of non-users is 23 ± 4.6, which is quite a large spread, particularly when the age of onset figure for users is 19 ± 2.5. The evidence of a better pre-morbid personality might suggest that those individuals would not have become psychotic if they had not used LSD. Also the two groups differed in number from each other (one group twice as large as the other) which clearly could have skewed the results.

Roy (1981) tried to replicate Breakey et al's results. He used a sample group of 37 Chronic Schizophrenics who had used LSD with controls who had not. He found no difference in the age of onset or hospitalisation from those without a history of drug use. Thus Breakey et al's study findings were not replicated.

Hensala et al (1967) compared 20 LSD using hospitalised patients with non-LSD using psychiatric inpatients. He found that the LSD using group was generally younger and contained more charactologically disordered individuals. 70% of these had had psychiatric treatment, of which two thirds was prior to LSD use. However the study is confounded by the patients' use of multiple drugs. Hensala argues that it is not LSD that is producing a new variety of patient but that a group of patients already using drugs has added LSD to their list of drugs to be used.

Consequently these methodological difficulties and the lack of replication do not lend the idea of LSD precipitating a psychosis earlier than would have happened anyway much credibility. Yet the implications of the acceptance of such research has led to warnings of adverse consequences. Other studies have shown that if an age cohort effect is taken into account, there does not seem to be a difference in onset between those who have used LSD and suffer Schizophrenia and those who have not but suffer Schizophrenia. The evidence does not suggest that LSD can accelerate such an onset.


Consequently it is interesting to note that Breakey's (1974) results have gained acceptance and continue to be perpetuated in the literature, despite having used unbalanced comparison groups, being confounded by polydrug use and having a large standard deviation over a small time span. For example Boutros and Bowers (1996) literature review only mentions Breakey's study, and offers no discussion or mention of the lack of replication by others, or of those studies demonstrating the converse. Yet the idea of LSD precipitating a psychosis continues to be regarded as a definite adverse effect of LSD.


Is LSD use only co-incidental with the onset of Schizophrenia ?

In examining the research on the use of LSD by people suffering from Schizophrenia, Stone (1973) argues that the use of LSD may simply accompany obvious and pre-existing Schizophrenia. The high incidence of substance use amongst individuals diagnosed as Schizophrenic, as well as the first onset of Schizophrenia, usually occur in the ages when individuals mostly experiment with drugs. As Henderson and Glass (1994) write, since LSD is used by the same age group in which early onset Schizophrenia appears, the two may be only co-incidentally associated.

Schneir and Siris (1987) have reviewed the literature on psychoactive substance use by individuals diagnosed as Schizophrenic. The studies reviewed show that this group uses significantly more hallucinogens (LSD etc) than in control groups. Johnston et al (1987) quantified this hallucinogen use by the mentally ill population as 11.45 %, which is substantially greater than in the general population (3.6%). (See Table 7)









Breakey et al


57% vs 30%

P = < .05

Higher lifetime prevalence of LSD use in Schizophrenic inpatients as compared with normal subjects.

McLellan & Druley


14% vs 5%

P = < .05

Higher lifetime prevalence of hallucinogen use by paranoid schizophrenic inpatients than with all other psychiatric inpatients. Figure became not significant when chronic schizophrenics were included with paranoid schizophrenics.





Of 105 inpatients with history of LSD use, 23% were diagnosed as Schizophrenic. Prevalence was twice that in the whole clinic population.

Tsuang et al


67% vs 40%

P = <.05

Hallucinogenic use was more prevalent amongst Schizophrenic substance users than non-schizophrenic substance users


Mueser et al (1990) in their literature review, argue that such studies of substance use suffer from methodological shortcomings, including lack of diagnostic rigour, inadequate sample sizes and confounding variables caused by polydrug use. Schneier and Siris (1987) similarly express concern at the methodological problems in the literature. They emphasise that studies do not differentiate between use and heavy use, and that studies have not included objective tests of drug use, such as urine tests, to exclude patients not wishing to say they had used drugs. Similarly, rates of substance use and preferences in substances used may simply reflect the local availability of such substances rather than their systematic use.


Whilst the high incidence of substance use amongst schizophrenics has been used to argue that such use precipitates or causes schizophrenia, alternative explanations suggest that such use is simply co-incidental or is used to self-medicate. Schneier and Siris (1987) discuss the 'medication' hypothesis, which explains the high use of substances as a form of self-medication to overcome either the side effects of prescribed medication or negative symptoms of their illness, such as dysphoria, apathy, withdrawal and lack of motivation. Also Test (1989) interviewed mentally ill outpatients, and found other reasons for substance use, such as to relieve boredom, anxiety or facilitate social contact.

Taylor and Warner (1994) write that between one quarter and a half of all Schizophrenics show premorbid personality and behavioural abnormalities (Grebb and Cancro, 1989). As the prodome to Schizophrenia is likely to be long and insidious, pre-schizophrenics may be more likely to use substances as a form of self-medication for prepsychotic symptoms, such as anxiety and insomnia. Ritzler et al (1977) suggests that the better pre-morbid personalities of LSD users who become psychotic, rather than suggesting that LSD has precipitated their psychosis, can be taken to mean that they are more active in their attempts to cope with the advancing problems from the onset of their psychoses. One such active attempt to cope is using LSD to reduce their stresses. Warner and Taylor (1994) argue that their research findings do not strongly support a precipitation argument but that LSD use is to manage uncomfortable affective states, etc.


Other studies have confirmed that people who are hospitalised who use LSD were more disturbed prior to their use of LSD (Table 8). McWilliams and Tuttle (1973) in their review of the literature on the long term psychological effects of LSD concluded that LSD can cause psychological difficulties in disorganised and disturbed individuals in less secure surroundings, without psychological support, at a time when emotional problems and crises are at their peak.








Frosch et al



Long standing Schizophrenia

Bowers & Freedman



Follow up revealed half had poor outcome




LSD used at time of life crisis. Third in psychotherapy. All had serious pre-existing pathology




Increased sociopathy and alcoholism in patients' families. Patients had much antisocial behaviour in their pre-drug histories

Blumenfield & Glickman



Psychiatric patients, of whom 72% had received prior psychiatric help.

Ditman et al



Unstable individuals, who had no support and found the experience disruptive

Robbins et al



Not previously thought psychotic




Seen as susceptible, unstable individuals




Found 28 extended psychoses. Patients had a lack of premorbid adjustment, but had no previous hospitalisations




Found to be unusually passive, frustrated individuals, with much unresolved hostility towards parents

Ungerlieder et al



Survey of professionals. 60% felt more than half of their patients were emotionally disturbed prior to LSD use. Post LSD however they had new symptoms.




ECT effected remission




Literature review. Concluded the worse the premorbid psychopathology, the higher the risk of a bad trip.




LSD users seeking to overcome feelings of lifelessness.



Whether the use of LSD can cause a prolonged psychosis is not evidenced in the literature, although case studies report that this does happen. This however is not confirmed by quantitative research studies. Studies using a prospective methodology would be best suited to determine this, but can no longer be employed for legal reasons. A study which did use a prospective approach reported no prolonged psychotic reactions. The literature is divided as to whether there is a difference between Schizophrenia and any psychosis thought to be a consequence of LSD use. If the use of LSD coincides with the first onset of Schizophrenia, this may be for a number of reasons, perhaps involving attempts at self-medication. The evidence of LSD advancing the onset of Schizophrenia is dubious, the research unclear in its use of controls, statistics and methodology.


 Chapter Three

Therapeutic Use

 "Why if they were worthwhile six months ago, why aren't they worthwhile now? …….perhaps to some extent we have lost sight of the fact that it [LSD] can be very, very helpful in our society if used properly."

Senator Robert Kennedy, Spring 1966



This chapter will evaluate the research into the use and effectiveness of LSD in connection with psychotherapy and the treatment of alcoholism. Whilst it was also used in work with the dying (Pahnke, 1969) and with children (Rhead, 1977) these areas have little literature and can be subsumed within the discussion on psychotherapy.


The literature concerning therapeutic uses of LSD within a medical context is vast. Grinspoon and Bakalar (1981) report that between 1950 and the mid 1960s there were more than a thousand clinical papers published discussing over 40,000 patients, in addition to several dozen books and six international conferences. Passie (1997) lists 687 publications, of which 100+ concern the efficacy of hallucinogen assisted psychotherapy.


The literature (Grof 1994, Caudwell 1968, Passie 1997, Grinspoon and Bakalar 1981) generally identifies two main approaches for the therapeutic use of LSD (Table 9). These are a) psychedelic therapy and b) psycholytic therapy. However Grof (1994) argues that this division is an oversimplification, and that the numerous therapists involved worked in very different, individual ways in using LSD in their treatments. Savage et al (1969) writes that the main difficulty in generalising such approaches is that whilst LSD was used in such widely differing ways for a diversity of purposes, they have all been 'lumped' together under the term 'LSD therapy'.


Similarly 'LSD therapy' was not done in the absence of other therapeutic practices. For example Fox (1967) reports that all her patients received, in addition to LSD, also antabuse, group therapy, psychodrama, Alcoholics Anonymous affiliation, counselling and analytically orientated psychotherapy. Consequently she suggests that few of her patients could say which of all of these treatments helped the most.




Psycholytic Therapy

Psychedelic Therapy


Activation and deepening of the psychoanalytic process with low doses of LSD (30-200mcg) by producing symbolic dream images, regressions and transference phenomena

High doses of LSD (300-800mcg) leading to so-called cosmic mystical experiences. Feelings of oneness, ecstatic joy and deep reaching existential insights are attained.


Psychodynamic frame of interpretation

Without foundations in classical psychological theories. New transpersonal approaches to explain structure and effects of the experiences.


10-50 required

1-3 overwhelming experiences are aimed for.


Analytic discussion of experience material on individual and group sessions, focusing on ego-psychology, transference and defence mechanisms. Attempt to adapt experiences to everyday life.

Very suggestive quasi-religious preparation, with the use of specific surroundings and music to structure the experiences. No psychodynamic interpretation. Psychedelic experience used to motivate changes in attitude and personality


Cure through restructuring of personality in a maturing process and loosening of infantile parental bonds. Better intrapsychic and social harmony.

Symptomatic cure, change of behaviour and better social adjustment triggered by conversion-like existential experiences and enhanced self-insight.

Two approaches to the use of LSD for therapeutic purposes (after Passie, 1997)


Psycholytic therapy.

Psycholytic therapy combined a series of administrations of low doses of LSD as an adjuviant to psychotherapy, usually following a psychoanalytic approach (Cauldwell, 1968). As Leuner (1994) states, this was not an autonomous treatment method, but a psychodynamically orientated treatment aided by an hallucinogen. This approach gained considerable support in Europe in the late 1950s. Passie (1997) shows that between 1953 and 1968 more than 7000 patients, identified from his bibliography, received a variety of psycholytic therapy.

Psycholytic means 'ego-loosening' and derives from the work of Busch and Johnson (1950) who initially thought that the administration of LSD and the resulting 'loosening of the mind' might enable patients to overcome blocks within psychotherapy, in the same manner as the effects of delirium and insulin shock therapy did.

Eisner and Cohen (1958) write that LSD was thought to aid five basic elements that are considered desirable in psychotherapy:

    1. It reduces defensiveness;
    2. Buckman (1968) argues that primitive defences, such as denial and projection, are no longer available to patients under LSD and they may experience, with enormous emotional impact, the denied aspects of their own personalities.

    3. It reduces resistance to uncovering repressed material;
    4. Buckman (1968) suggests that the patient has access to deeper feelings, which he and the therapist can accept, understand and integrate.

    5. It increases the ability to accept conflictual material;
    6. It enhances the patient-therapist relationship;
    7. Buckman (1968) notes that regression and transference are intensified leading to the emergence of early childish or even infantile memories and fantasies, which are significantly charged with emotion. If these are bought to light in the atmosphere of a therapeutic relationship based on trust, they can provide a corrective emotional experience for the patient.

    8. During the experience, consciousness remains intact and recall is amplified.

Cauldwell (1968), in his review of LSD psychotherapy, records that most researchers reported such increased extent of abreaction, transference and memory recall. Sandison, Spencer and Whitelaw (1954) describe that repressed memories are relived with remarkable clarity, with therapeutically beneficial consequences. Eisner and Cohen (1958) suggest that the use of LSD permits a rich view of the unconscious. Not only do they suggest that varying depths are possible with increasing dosages and number of sessions, but also that the patient retains the ability to follow both their own associations as well as the interpretations of the therapist. This permits a dramatic opportunity to trace problems back to their origins. Grof (1994) argues that this approach achieved solid and permanent results because any unconscious material was 'worked through' in the accompanying psychotherapy.

However the benefits of using such an adjunct to psychotherapy were thought also to have drawbacks. Eisner and Cohen (1958) warn of the likelihood of triggering a psychosis (see previous chapter) or suicide in particularly vulnerable patients. In terms of continuing effects, such as 'flashbacks' described above, they comment that their patients who experienced such effects found them 'relaxing and beneficial'. Grof (1994) writes that with properly supervised LSD sessions and psychotherapy, patients can be helped through difficult points safely.

Pos (1968) argues that from his clinical experience that the loosening of the ego, and in particular of the defence mechanisms, did not necessarily happen. Sometimes particular personality features remained in focus, such as obsessional and repetitive preoccupations. Whilst LSD may dissolve weaker defences, as in near psychotic or near psychopathologically adjusted individuals, it may not dissolve stronger ones. He argues that the usefulness of a psychedelic treatment is impossible to predict, and that unexpected acting out by the patient may be a serious challenge to the therapist.

Grof (1994) reports that whilst low or medium doses of LSD activate latent unconscious material very effectively, bringing it closer to the surface, it is not so overwhelming as when using higher doses and therefore may 'allow' an unwilling subject to avoid material that perhaps should be examined. Also whilst any transference is enormously intensified, this can present both opportunities and dangers. Grof's observations suggest that the intensity of the transference is directly proportional to the resistance to facing the original traumatic material. If the therapist puts great emphasis on identifying and analysing the transference instead of acknowledging it and directing the patient's attention beyond it, the therapist is in fact colluding with the patient's defence mechanisms.

Again since psycholytic therapy is theoretically rooted in conventional egodynamic psychotherapy, the spiritual and mystical dimensions of the LSD experiences are thought to be regressive impulses, which need to be interpreted and worked through. In contrast psychedelic therapy (described below) holds these experiences to be fundamental to personality change, and hence healing; not to be interpreted but to be encouraged and experienced. Consequently from a theoretical position psycholytic and psychedelic therapy are incompatible.

Richter (1994) critiques the use of psychoanalytic techniques in psycholytic therapy. He argues that as described they do not meet the requirements of psychoanalysis. The published literature ignores the interpretation of the prescription of the drug on the transference between patient and practitioner. The clinical publications do not describe or interpret countertransference. He concludes that most of the LSD psychotherapists had either abandoned or had never practised basic psychoanalytic techniques. Although the effects of LSD are useful in psychotherapy, Richter argues that they are not sufficient for therapeutic change. It is not just insight that is required, but the painful analysis of resistance, transference and its resolution.


Psycholytic research

The literature contains numerous publications whose authors claim improvements in their patients (for example Grof, 1994) using case histories in support of their claims. Literature reviews (Eisner and Cohen (1958), Hoffer (1967), Leuner (1994), Kurland et al (1971)) similarly give compendiums of such success claims.

In evaluating psycholytic therapy's efficacy, Brill (1967) shows that most therapists practising this approach reported long term improvement in 2/3rds of their patients, who were usually difficult or chronic neurotic patients. Mascher (1967) has produced a synopsis of indications for psycholytic therapy from 42 publications by 28 therapists concerning a total of 1603 patients (Table 10).






Number of Publications


Very good/good (%)

Anxiety neuroses



Irritable depression



Character neuroses and sociopathies



Borderline cases



Perversions and homosexuality



Compulsive neuroses



Hysteria and conversion



Dependency on alcohol and tablets



After Mascher, 1967.

Mascher's (1967) research demonstrates that there is considerable efficacy in the use of psycholytic therapy with anxiety neuroses, irritable depression and character neuroses. However in view of the considerable variance in methods and treatments applied to patients, Mascher's figures remain problematic as evidence. Leuner (1994), acknowledging the problematic nature of comparing results obtained under very different circumstances, argues that at least they allow a 'first preliminary clinical overview' of a favourable treatment outcome.

Against such a favourable overview, Richter (1994) argues that whilst the therapists always claimed excellent results for their treatments, their research methods were typical of the earliest phase of psychotherapy research. Yet Eysenck's (1952) general critique of psychotherapy research did not alter how LSD's use in psychotherapy was researched. It could be argued that this shows ambivalence towards improving the rigor of their research. Similarly after LSDs prohibition the legally possible follow up research on those already having been subjected to such treatment was also not pursued. This would have been important in determining efficacy and improvements over time. When researchers were no longer able to administer LSD this also seemed to detract from follow-up research. Passie (1997) shows a dramatic fall off in LSD studies after its prohibition (in the United States) in 1966.


Psychedelic therapy.

Psychedelic therapy utilises a single large dose of LSD to induce a profound psychedelic peak experience of such intensity that permanent personality change ensues. Grof (1994) shows that psychedelic therapy was derived from research with alcoholics. Hoffer (1967) noticed a similarity between the effects of delirium tremens and the effects of psychedelic experiences. Jensen (1994) records that they attempted to deter alcoholics from alcohol by frightening them by mimicking the effects of delirium tremens with LSD. However it was found that those who did change were motivated not by fear but by experiences of transcendental beauty and meaning, particularly when these experiences had a very definite religious or mystical emphasis. Grof describes this as creating optimum conditions for 'ego death' and subsequent transcendence into the 'psychedelic peak experience',

'…..an ecstatic state characterised by the loss of boundaries between the subject and the objective world, with ensuring feelings of unity with other people, nature, the entire universe and God……They speak about cosmic unity, unio mystica, mysterium tremendum, satori, moksha, or the harmony of the spheres.' Grof, 1994

Grof (1994) suggests that such psychedelic experiences enabled a greater acceleration and deepening of the therapeutic process. It emphasised the positive, and did not concentrate on psychopathology or traumatic material. However it was a 'hit or miss' procedure, and there was no guarantee that all individuals would have a deep, transformative experience.


Ludwig et al (1970) shows that this radically different form of treatment engendered criticism from the medical establishment reacting emotionally, since it ran counter to the established doctors' epistemological security, their usual materialistic, scientific outlook. Some thought that as it didn't conform to the usual long psychotherapy process, it smacked of instant cures, charlantary and magic. A problem for the established views in psychology was that the psychedelic process was not linear, rational or logical in its approach to knowledge. It may produce very dramatic changes with minimal understanding of the underlying mechanisms. However Grof argues that because of the enormous variability between individuals, this precludes any valid generalisations based on the material from single sessions with many different subjects, until an adequate paradigm for their understanding is developed.

Since reliance was made on one to three single large doses of LSD, the researchers felt no need to accompany this with long-term psychotherapy. Kurland et al (1971) argues that since this approach happened without long-term psychotherapy, the initial dramatic improvements seen in subjects were mostly not long lasting.

Passie (1997) reports that, as identified from his bibliography, over 2500 alcoholics, drug addicts and neurotic patients were treated using this approach between 1957-73.


Treatment of alcoholism.

Since both psycholytic and psychedelic therapies were used in the treatment of alcoholism, they can therefore be compared in terms of their treatment efficacy with each other.

Abuzzahab and Anderson (1971) reviewed 31 published studies, which involved 1105 patients. 18 studies used a psychedelic approach, 5 with controls. 7 studies used a psycholytic approach, 3 with controls. From their review they argue that the evidence does not support LSD's effectiveness in treating alcoholics. It was difficult for Abuzzahab and Anderson to reach meaningful generalisations from the variety of published investigations because of the different designs and varying criteria concerning improvement. However surprisingly they offer a summary (Table 11) of the aggregated results, which suggests that if controls are used to validate results, an improvement resulting from a large single (psychedelic) dose occurs in 75% of the patients.

 However this result is misleading and is biased by two studies. They argue that generally the use of control groups dramatically demonstrated that LSD was not the cause of any improvement. Most studies that employed such controls failed to detect differences in efficacy of alternative treatments. Ludwig et al (1970) write that in their study there were no substantial gains just for the LSD group; any gains were similar to those in the control groups. They argue that had it not been for the control groups the gains by the LSD group would have seemed most impressive, but were not actually better than simple exposure to the hospital ward.





Type of study

Number of studies

Number of patients (mean/study)

Improvements (%)





Psychedelic Studies

Without controls


408 (31.4)



With controls


384 (76.8)



Psycholytic Studies

Without controls


39 (7.8)



With controls


274 (91)



After Abuzzahab and Anderson (1971)

The figure of 75% improvement from the psychedelic therapy actually arises from the results of two studies by Jensen (1962, 63) showing such positive results. The other three studies utilising controls failed to show significant differences between control groups and those who had used LSD. Unger (1963) offers a critique of Jensen's studies. He argues that

    1. there is ambiguity about the assignment of patients to different treatment groups - it does not seem to have been entirely random. Indeed in the 1962 study, patients with a greater likelihood of improvement were selected for the LSD group, rather then the control group, creating a bias between the two groups.
    2. the effects of assuming that patients who left or refused follow up contact could be categorised for statistical purposes as 'treatment failures' is misleading. Indeed because patients did not complete the therapy does not mean there was no improvement. Since the control group was half the size of the study group, and over half of these did not complete the treatment, the validity of the control group is undermined.
    3. Consequently this critique throws doubt on the validity of the report of a 75% improvement. The studies with controls (bar Jensen's) do not show major differences between groups which used LSD and those that did not.

       Abuzzahab and Anderson (1971) argue that there are three methodological problems that contribute to the confusion about efficacy of LSD use with alcoholics. These can also be applied to the use of LSD in treatment as a whole:


      1. the investigators themselves

In critiquing the researchers, much use has been made of validating results within positivist frameworks, rather than within the more interpretative paradigm within which the therapy was given at that time. Subjective experiences and self-reports were given credence and were reported in the form of case studies. Also suggestions were made that the therapists involved should also have had a psychedelic experience themselves to be able to understand the patient's experience.

Consequently, critics from the more positivistic backgrounds, like Cole and Katz (1964), argued that that many of the claims for the successful use of LSD were not based on detailed, carefully controlled studies designed to be free from possible distortions due to bias or enthusiasm. They argue that the investigators had lost objectivity, particularly as they may also have taken LSD during the therapy session to increase empathy with the patient. A noted critic of LSD therapy was Grinker, editor of an influential psychiatric journal, (The Journal of Nervous and Mental Disease), who argued that the taking of LSD by the therapists effectively disqualified them from meaningful research.


Whilst a double blind methodology would control for any investigator bias, this would be difficult, if not impossible, for LSD, since the effects of LSD would immediately distinguish those subjects who had taken it from those who had not.

The majority of reports of the results of the use of LSD in psychotherapy are contained in case histories or subjective accounts of such patients as was the norm in research reporting at the time. Grinspoon and Bakalar (1986) argue that such case histories can always be questioned as anecdotal on grounds of the potential effects of placebos, spontaneous recovery, or special and prolonged attention from the therapist. However whilst this criticism was made of LSD treatment, it is still an important question in all psychotherapeutic research in general, with or without LSD.

On the other hand, Salzman (1969) argues that in any evaluation of drug effects, anecdotal or descriptive accounts often precede rigorous controlled experimentation. These should therefore be viewed only as preliminary reports of effects, subject to later verification. However the verification never came.

2. The patients

Abuzzahab and Anderson (1971) argue that alcoholics are not all the same. They form a heterogeneous group, having a wide variety of personalities, backgrounds and, sometimes, complex physical complications secondary to alcoholism. Clearly no research could separate out all the interactions here.

Similarly measures are required to indicate differences in severity. Some studies use different variables, such as the number of years drinking, amounts per day or the degree of disruption of psychosocial adjustment.

Consequently the research to date would need far firmer and agreed controls, selection procedures and outcome measures to determine any efficacy. However the studies which used control groups seem to have demonstrated that LSD was not efficacious in the treatment of alcoholism.

3. experimental design

Abuzzahab and Anderson (1971) argue that criteria are needed to measure improvements in areas such as abstinence, moderation, improvement in relationships, or vocational attainments. Grinspoon and Bakalar (1986) argue that the most serious flaws in the research were the absence of controls, inadequate follow up and the lack of a double blind approach. In forming outcome criteria, Ludwig et al (1970) agues that such scales would be difficult to determine. He asks rhetorically what are changes for the better, and for whom and who decides this. Feeling different and being different are not the same thing. Insights should lead into action, and are not just words. He argues that it is difficult to claim any intrinsic scientific validity for such moralistic and relativistic criteria for improvement.


Evidence that LSD is effective in facilitating therapeutic change is demonstrated in the literature by means of therapist's case reports, claims of improvement and by accounts of the patients involved. However, when control groups are used to validate therapy with LSD, only one author claims significant success. His research however can be questioned on his selection procedures. The use of LSD to facilitate therapeutic change was not confirmed by research using positivist methods.










This dissertation has re-evaluated the theory and research evidence in relation to the positive and negative effects of LSD on the mental health of the person using it. The outcome of this study, as identified in the objectives described in the introduction, can now be summarised. 

1. The Research Literature

In searching the research literature for this dissertation, the author identified that the literature is significantly incomplete in five areas:

  1. There is a significant lack of prospective studies to determine the incidence of flashbacks utilising the theoretical approaches outlined in this dissertation;
  2. There is a reliance on case studies on the incidence of psychoses following LSD use, which does not give present day credibility to the discussions;
  3. The research on 'normal' populations is clearly insufficiently controlled, nor is it necessarily representative of the 'normal' population;
  4. The literature demonstrates a gender imbalance in populations researched, with an over use of male drug users;
  5. There are very few follow-up studies researching the thousands of individuals who were treated with LSD, or who received LSD in conjunction with psychotherapy.

2 Research on Flashbacks

Chapter one discussed the extent to which research and theory shows that a relationship exists between LSD and flashbacks. It was established that research found that 77% of LSD users do not report that they experience flashbacks. For them there is no such relationship. The remaining 23% of users who report flashbacks can be explained by a number of 'non-pathological' theories which focus on personal qualities of suggestibility, role play behaviour and its reinforcement, unconscious thoughts or feelings, or the noticing and mislabeling of normally occurring perceptions that are usually not noticed. However there are more reports of the experiencing of flashbacks from psychiatric populations.

This evaluation of the research literature suggests that to label flashbacks as 'adverse effects' of LSD is misleading, and not in accord with either the research or the explanatory theories in the literature. Present day warnings that LSD causes flashbacks simply echo those of the sixties as part of the anti-LSD hysteria. They are not supported by the literature.

3 LSD and prolonged psychoses

Chapter two discussed the extent to which research and theory substantiated that the use of LSD precipitates a psychosis. Whilst legal restraints presently prohibit prospective studies, the large surveys of the 60s and 70s show that in medical settings incidence of prolonged psychoses following LSD use is small, and not much higher than that of the general population. This is not necessarily unusual, since the populations studied comprised psychiatric patients where a higher incidence would be expected.

Perhaps some of the confusion arises from the difficulties in distinguishing a psychosis caused by a mental illness, such as Schizophrenia, from a psychosis peculiar to LSD. This is further confused in the literature by not taking account of an age cohort factor, that younger people have a greater exposure to hallucinogenic substances and that an early onset schizophrenia can coincide with the age that younger people experiment with drugs. This is further confused by the higher use of hallucinogens by people who have Schizophrenia.

The literature shows that LSD does not advance the onset of Schizophrenia. The one study that comes to the opposite conclusion, despite its methodological weaknesses, is the one that continues to be reported in the literature reviews. Whilst case studies report that LSD precipitates psychoses, this is not confirmed in positivist research.

It would seem that the evidence for or against LSD use precipitating a psychosis is too limited in scope, with too many confounding variables, to arrive at a firm conclusion one way or the other. This is surprising since the notion that LSD use causes psychosis was one of the principal reasons for the prohibition of LSD.

4 Therapeutic uses

Chapter three discussed the extent to which research and theory substantiates that LSD is an important aid in psychotherapy. Clearly the studies do not meet present day methodological requirements for their validity. They do not address non-specific therapeutic issues. Consequently it is difficult to draw conclusions from them.

Chapter three discussed the extent to which research and theory substantiated that LSD is an aid in working with alcoholism. Whilst positive results were generally claimed in uncontrolled research, when control groups were employed there were only minimal differences between those groups which used the LSD and those that did not. The very positive claims from one author seem to arise from methodological flaws and biased selection procedures. It seems that LSD use in treating alcoholics was not superior to any of the other therapies practised.


In conclusion, whilst numerous authors offer case studies showing both positive and negative effects of LSD on their subjects, it would seem that LSD is not demonstrated by research in the literature to have positive or negative effects on those who use it in terms of flashbacks, psychosis or therapeutic use in psychotherapy or in the treatment of alcoholism.




There are six recommendations arising from this dissertation, concerning both further research and policy considerations.

Recommendation One

The first recommendation concerns the huge potential for follow-up research on those individuals who received pharmaceutically pure LSD as part of their medically supervised treatment in the 50-70s. For example, here in the UK over 4500 individuals received such treatment (Malleson, 1971). Given the long intervening period, researchers could investigate the long-term benefits/adverse effects on these individuals' lives. Of particular interest would be qualitative research of individuals' thoughts and feelings in retrospect about their treatment, beyond those of their doctors' reports. This could include accounts of those individuals claiming compensation for continuing unwanted effects (Guardian, 11/10/95). The author recommends that this research is carried out.


Recommendation Two

The second recommendation concerns the writing of a detailed history of the period and practices of the use of LSD as treatment by psychiatry. Such a history is not in the literature. This should include patients' views, in addition to those of the nurses, therapists and other staff involved, particularly in view of accounts of atrocious and unethical practices. The author recommends that this history is written.

Recommendation Three

The third recommendation concerns the development of new educational material in light of the research re-evaluated in this dissertation. This has shown that two of the grounds for the prohibition of LSD, allegedly on medical grounds, are not substantiated by the research literature. Yet such views continue to be perpetuated by the media, by doctors and politicians and are included in education packages.

Such education packages need to be reformulated to outline alternative theoretical approaches, outlined in this dissertation as explanations for 'flashbacks', and not to resort to simplistic statements about LSD producing such events. Similarly the history of the prohibition of LSD is incorrectly being represented as the work of benevolent doctors, rather than the continuation of a cultural repression of psychedelic experiences in yet another guise. Alternative approaches to the use of LSD, for example in the generation of mystical religious experiences, consciousness expansion and personal understanding should also be included.

Similarly evidence based knowledge of LSD should inform clinicians, and other mental health workers, practices. This would entail the more careful reporting and recording of individuals with psychopathologies allegedly stemming from the LSD use. In discussions with users and their relatives, a more balanced, evidenced-based approach can be developed.

The author recommends the development and dissemination of such educational material.


Recommendation Four

The fourth recommendation concerns the development of a harm minimisation approach to LSD and its users. If there is no clear evidence of direct harm from the use of LSD itself, there is a need to minimise damage caused by the prohibition itself. This would involve the dissemination of balanced factual research based information, in addition to the provision of pharmaceutically pure LSD, in known doses with clear instructions and cautions. This would free LSD from its' underworld associations and production on the black market, and protect users from the potentially harmful effects of buying substances whose composition is not known.

The author recommends the development of such a harm minimisation approach to LSD.

Recommendation Five

Recommendation five concerns the need to utilise modern methodologies, with appropriate control groups, to enable the data to be considered seriously in present day practice, now that human research is recommencing. Careful screening for pre-existing psychopathologies could be used so that they could not be confused with the consequences of LSD use. Similarly an appropriate rating scale for assessing change in the individual as a result of the psychedelic experience would need to be (re)developed. The author recommends that such approaches are employed in new research.


Recommendation Six

The sixth recommendation calls for a re-evaluation of the research literature of the other 'adverse effects' identified in the literature, such as LSD induced suicide, bad trips and adverse long-term character distortions. In view of the ambiguities, gaps and inadequate methodologies employed in the research on flashbacks and prolonged psychoses, other adverse effects may also not actually be demonstrated by research. The author recommends that this re-evaluation is carried out.


Personal comments

This dissertation has been particularly interesting for me on several accounts. Not only has it given me the opportunity to increase my academic research skills in a focused way, it has also introduced me to the valuable resources on the Internet.

I am surprised at the gaps in the literature identified above, particularly as LSD has been available since the early 1950s. The research on flashbacks and prolonged psychoses still is very much incomplete. I was particularly surprised at the lack of follow-up research of the thousands of patients who were given medically administered LSD as part of their treatment.

If I were to research this subject again I would concentrate on the additional 'adverse effects' identified in the literature concerning LSD induced suicide, bad trips and adverse long term character distortions. I wonder how conclusive the research on these subjects is ?



I would like to thank my tutor, Martin Giddey, for his help and guidance for this dissertation. Similarly I would like to thank my partner, Sally Harper for her patience and understanding whilst I was engaged in my researches for this study. Finally I would like to thank the staff at the Postgraduate Library at the Royal and United Hospital, Bath and at the Libraries of the University of Portsmouth for obtaining the numerous research articles needed for this study.



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