Purpose: Psychological; to investigate any possible relationships between ecstasy use and presence of mental disorders in a representative sample of adolescents and young adults residing in the Munich (Germany) area.

Design: Prospective (non-experimental) between-groups, longitudinal design, with drug use (ecstasy use, polydrug use-no ecstasy and no illicit drug use) serving as the between-groups factor and time of measurement (baseline, first follow-up, second follow-up) serving as a repeated measure.

Subjects: 2462 young men and women, including 211 ecstasy users, 1008 polydrug users and 1329 non-drug users [2548 at second follow-up), aged 14-24 at baseline, residing in the Munich (Germany) area and recruited through selection of participant from registries of residents. This sample is a sub-sample of 3021 people interviewed, reflecting those contacted at least during second follow-up). Matching - As this was a prospective non-experimental design with a representative sample, no matching took place, though all participants fell within the same age group. Research finding from this sample or sub-samples of the sample have been previously been published (Schuster et al. 1998; Von Sydow et al. 2002).

Criteria for Inclusion - Ecstasy users - Reporting at least one use of ecstasy over lifetime at second follow-up. Polydrug users - Having reported use of other illicit drugs at least once at second follow-up. Non-drug users - No reported use of any illicit drugs at baseline or at either first or second follow-up. All groups - Residing in the Munich area, being between the ages of 14 and 24 at baseline, having answered drug use questions at second follow-up and at least one earlier point in time.

Drug Use Parameters - No information was reported on drug use parameters beyond the grouping of ecstasy users, polydrug-no ecstasy users and non-drug users. 211 of 2462 reported at least one use of ecstasy. Previous reports presented information on frequency of ecstasy use in 1998 and reported that 3% of regular users (reported 5 or more uses) of ecstasy and related substances used ecstasy daily, 14% used 3-4 times a week, 29% used 1-2 times a week, 34% used 1-3 times a month and 20% used less than once a month. No information is provided on time of last use prior to interviews at baseline or at second follow-up. Other drugs - No information is provided concerning use of other drugs either by ecstasy users or by polydrug users. However, text indicates that 93% of ecstasy users and 95% of polydrug users reported some cannabis use, 39.1% of ecstasy users and 6.5% of polydrug users reported cocaine use, and 21.4% of ecstasy users and 3.9% of polydrug users reported opiate use. Previous reports indicate that ecstasy users also used hallucinogens (Schuster et al. 1998).

Group Demographics and Matched Variables - The authors drew samples from people aged 14-24. Gender - No information is provided concerning gender of overall sample or sub-samples. Men were more likely to report having used ecstasy than women. Age - No information provided on average age of sub-samples. At baseline, people aged 16-21 were sampled at twice the probability of estimated numbers in population, and people aged 21-24 at baseline sampled at half the estimated probability of the actual population percentage. Education - Information presented as weighted percentages (weights used to take into account sampling bias for younger people at baseline). No averages presented; highest percentages for all 3 groups were either in non-university preparatory secondary school ("fachoberschule") or university preparatory secondary school ("gymasium"). 24.4% weighted percentage of ecstasy users were in non-university secondary school, and 41.2% of ecstasy users were in university preparatory school. 21.8% of polydrug users were in non-university preparatory school and 43.8% were in university preparatory school. 22.6% of ecstasy users were in non-university preparatory secondary school, and 40.0% were in university preparatory school. However, significantly fewer ecstasy users were enrolled in university than polydrug users or non-drug users (5.6% ecstasy users versus 9.7% polydrug users and 13.5% non-drug users.

Measures: Demographic Questionnaires - Demographic characteristics measured via interview at baseline and at second follow up included education, living situation (with parents, alone, with partner), employment, marital status, social class and financial situation.

Mental Disorders - A full diagnostic interview based on DSM-IV was conducted at baseline and at second follow-up, with diagnosis covering substance abuse disorders, anxiety disorders, mood disorders, eating disorders and somatoform disorders, but apparently not covering schizophrenia. Information on utilization of health care resources also gathered during interview.

Analyses: Cumulative lifetime incidence of DSM-IV mental disorders calculated by adding diagnoses made at baseline, first follow-up and second follow-up. Strength of association between presence of mental disorder and ecstasy (and related drug) use was examined viva odds ratios. To control for possible artifacts due to a greater percentage of younger people participating in all 3 follow-ups,, associations tested for interaction with age, and if significant interactions between age and a drug-related variable were found, then separate analyses were performed for younger and older cohorts. All analyses used weights to control for differential probabilities associated with age, gender and geographic location to match the distribution seen in the general population. Analyses examining associations between ecstasy use and mental disorders controlled for demographic factors found to vary with ecstasy use, including age, gender, education, employment, social class and living arrangement.

Temporal analysis - Whenever age of first use predated diagnosis, use was referred to as "temporally primary," and when diagnosis of mental disorder preceded age of first ecstasy use, use was referred to as "temporally secondary."

Results - Significant Differences Found: Demographics - At baseline, men were more likely than women to use ecstasy, and ecstasy users were more likely to be younger than older. Likelihood of ecstasy use decreased with increasing likelihood of attending university-preparatory secondary school ("Gymnasium") or university, when comparing across ecstasy users and non-drug users. At second follow up (in analysis controlling for age and gender), ecstasy users were less likely to attend university than either polydrug users or non-drug users. At second follow-up, ecstasy users more likely to be unemployed than polydrug users or non-drug users, and they were more likely to report being from a lower social class. Ecstasy users were more likely to report living alone and being unmarried than were non-drug users (but not polydrug users).

Ecstasy use and Mental Disorders - 68% of those reporting at least one ecstasy use reported a history of at least 1 DSM-IV mental disorder. Users of ecstasy and related drugs were more likely to report having alcohol or substance abuse disorder than polydrug users or non-drug users. Ecstasy users were more likely than non-drug users to be diagnosed with affective disorders, anxiety disorders, somatoform disorders and eating disorders, and diagnosis with a DSM-IV mental disorder was higher in ecstasy users than polydrug users, though the difference in likelihood of diagnosis with a psychiatric disorder in ecstasy users and polydrug users was less pronounced than differences between ecstasy users and non-drug users. Suicidal ideation was more commonly reported in ecstasy users than in non-drug users. Alcoholism and Bipolar I disorder were more commonly diagnosed in the younger cohort, and panic disorder and somatoform disorders were more commonly diagnosed in older respondents; due to the unsystematic variation in age interactions, they were not controlled for in analyses.

Temporal analyses - Overall, diagnosis with mental disorder appeared to precede onset of ecstasy use. Diagnosis with mental disorders still preceded age of onset for ecstasy use when analyses controlled for presence of substance abuse disorders. The most frequent prior diagnoses were: specific phobia, social phobia, alcohol/substance abuse, and somatoform conditions. Mental disorders seen after the onset of ecstasy use were major depression, phobia, panic disorder, agoraphobia, generalized anxiety disorder, and eating disorder. Results-No Significant Differences: Demographic variables - At second follow up, ecstasy users, polydrug users and non-drug users were equally likely to have dropped out of school or to have attended all other schools (basic school, non-university secondary school, university-preparatory secondary school). Ecstasy users were not more likely than polydrug users to be divorced or widowed at second follow up. Ecstasy users, polydrug users and non-drug users were equally likely to be living with partners. Ecstasy users, polydrug users and non-drug users were similarly likely to be students or to have job training.

Temporal analysis - There was no significantly greater likelihood of those reporting ecstasy use at baseline to be later (at follow up) diagnosed with a mental disorder than those reporting no ecstasy at baseline.

Overall Effects: Associations between use of ecstasy and related drugs (other substituted amphetamines, amphetamines) and mental disorders were examined in a representative sample of Munich residents between the ages of 14 and 24, using a prospective, longitudinal design. Respondents who used ecstasy were more likely to be young and male than those reporting no ecstasy use. When compared with adolescents and young adults reporting use of other illicit drugs and respondents reporting no illicit drug use, ecstasy users were less liable to be enrolled in a university, were more likely to be living alone or with friends, to be unemployed and to belong to a lower (versus higher) social class. Beyond these differences in demographics, use of ecstasy and related drugs was strongly associated with diagnosis with at least one mental disorder, including substance abuse disorders, affective disorders, anxiety disorders, eating disorders and somatoform disorders. Ecstasy users were particularly more likely to be diagnosed with a substance use disorder. Simple phobia, social phobia, substance abuse disorders and somatoform disorders were especially likely to precede ecstasy use, while major depression, a host of anxiety disorders (panic attacks, generalized anxiety disorder, simple phobia, agoraphobia) and eating disorders were most likely to appear subsequent to initiation of ecstasy use. However, it appears that most diagnoses of mental disorders were made before onset of ecstasy use. This remained true even when controlling for a preceding diagnosis of substance abuse disorders. As well, ecstasy users were no more likely than non-drug users to be later diagnosed with mental disorders. Hence the association between ecstasy use and psychiatric illness may not result from neurotoxic or other effects of ecstasy but instead occurs because people with mental disorders, particularly anxiety disorders, are more likely to use ecstasy than people without these disorders, perhaps as a form of "self medication."

Comments: This report is one of several reports on ecstasy use in representative samples of young residents of Munich published by the same authors. Previous reports have provided information on the percentage of young people using ecstasy and related drugs, including those diagnosed with ecstasy dependence, and the course of ecstasy use. These studies found that use of ecstasy and related drugs seems to decline over time. Findings presented in this report are consonant with a growing number of studies (e.g. Daumann et al. 2001; Morgan et al. 2002) suggesting that psychological problems and psychiatric disorders reported in ecstasy users cannot be considered direct results of ecstasy use. Unlike findings from studies reported earlier this year, the findings reported by Lieb and colleagues are drawn from a representative sample, and not those contacted via snowball sampling or recruitment through advertisements, and the sample size is notably large. Furthermore, the study employed a prospective design. Hence these research findings offer some of the strongest support for claims that adolescents and young adults who use ecstasy and related drugs are more likely to suffer from a pre-existing mental disorder before initiating use, suggesting that ecstasy use in this population may be an attempt at "self-medication." However, it is also interesting to note that major depressive disorder is more likely to appear after onset of ecstasy use. The association between membership in a lower social class and ecstasy use found here is also reported in a survey of men in Northern Italy entering military service (Siliquini et al. 2001), and stand in contrast to assertions that ecstasy users in North America are not more likely to be from a lower social class. One study limitation is that, in an attempt to address uncertainties concerning the contents of illicit ecstasy, the authors use a broad definition of ecstasy to refer to any substituted amphetamine or amphetamine itself. Hence ecstasy users may be respondents reporting (presumably intentional) use of amphetamines, and not just those using substituted amphetamines. It is possible that combining users of these drug classes has obscured relationships specifically associated with use of substituted amphetamines.