Skip to content

Acute Adverse Reactions to Lsd in Clinical and Experimental use in the United Kingdom

Nick Malleson

The British Journal of Psychiatry February 1, 1971 DOI: 10.1192/bjp.118.543.229 (opens in new tab)

Study at a glance

AI-extracted from the abstract
Characteristics Survey Peer reviewed
Sample size 5,000
Population Subjects in LSD or mescaline sessions
Interventions LSD mescaline
Topics Mescaline LSD
Keywords Psychosis Adverse effect Subject documents Hallucinogen Pharmacology
Citations 110
Key findings In a survey of 5,000 subjects across 25,000 LSD or mescaline sessions, only two suicides were directly related to LSD, and psychotic reactions lasting over 48 hours occurred at rates of 0.8 per 1,000 experimental subjects and 1.8 per 1,000 patients.

Abstract

It is well recognized that LSD (lysergide) can give serious adverse reactions, including suicide and prolonged psychosis; Smart and Bateman (1967) have reviewed the subject thoroughly. However, examples reported refer largely to cases where the LSD was self-administered. Medical case reports usually cover small case numbers, and publication may be determined by high adverse reaction rates. There has been no methodical survey of the pooled experience of psychiatrists since Cohen's study in 1960. This reported 44 replies sent out to 62 American investigators who had published papers or whose work was known to the author. Replies covered 5,000 subjects with 25,000 LSD or mescaline sessions. In this series, there were only two suicides that Cohen regarded as directly related to the LSD, and there were psychotic reactions (lasting more than 48 hours) at a rate of 0·8 per 1,000 experimental subjects and 1·8 per 1000 patients. It is unfortunate that one-third of the investigators failed to reply to Cohen's questionnaire.

Explore topics