Psychedelics and Psychiatric Drugs: NIMH Update

Summer 1994 Vol. 05, No. 1 Politics and Protocols: In Search of a Balance

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In the last MAPS newsletter we alerted readers to a study we are conducting at the National Institute of Mental Health on the interaction of hallucinogens and antidepressants, asking to interview people who have taken both of these types of drugs at the same time. The response to this request was tremendous and we’d like to thank everyone who took time to be interviewed about their experiences.

What we’ve been finding seems to break down into two types of responses, dependent on which class of antidepressant a person was taking. Those people who had been taking an antidepressant with selective effects on the serotonergic systems in the brain (drugs such as Prozac, Zoloft, Paxil) and then took LSD had a greatly diminished response to the hallucinogen. This decrease in response to LSD was also seen in those people who had been taking an MAO inhibitor.

In contrast, people who had been taking tricyclic antidepressants (such as Tofranil, Norpramine), which have primary effects on norepinephrine systems in the brain, and then took LSD had a potentiated response to the hallucinogen. This is similar to what happened to people who were taking lithium, either alone or in combination with a tricyclic antidepressant — there was also an increased response to LSD.

I have had only one report with MDMA thus far. A person took MDMA after taking an MAO inhibitor and had a hypertensive crisis (he collapsed for several hours). This is a very dangerous and potentially fatal combination which could have been anticipated based on the way both of these drugs work. Do not try this at home!

Please note that all the reports we received were from people who had been taking their antidepressants for at least 4-6 weeks. This is the timeframe when biochemical systems in the brain are significantly altered and therapeutic effects begin to occur. We do not know what the effects of short-term use of antidepressants might be on the hallucinogenic response.

This study is important because it helps scientists to better understand both how hallucinogens affect neurochemical systems as well as to understand how antidepressants act in the brain. The case reports that we have gathered (numbering over 40 now!) will be presented at the Serotonin Club meeting in Chicago at the end of July and will be submitted for publication soon afterwards.