Human hallucinogen research: guidelines for safety.

Human research with classical hallucinogens has recently resumed. Although these drugs are physiologically safe and not addictive, they carry psychological risks, most commonly overwhelming distress during drug action (a 'bad trip') that can lead to dangerous behavior. Rarely, prolonged psychoses may be triggered. Safeguards include excluding volunteers with personal or family histories of psychotic or severe psychiatric disorders, building trust and rapport before sessions, careful preparation, providing a safe physical environment, and having at least two monitors present during sessions. Follow-up should probe for hallucinogen persisting perception disorder, which is rare when guidelines are followed. Incautious research risks participant safety and future research, but careful studies may inform psychiatric treatment and basic science.

Study at a glance

Abstract

There has recently been a renewal of human research with classical hallucinogens (psychedelics). This paper first briefly discusses the unique history of human hallucinogen research, and then reviews the risks of hallucinogen administration and safeguards for minimizing these risks. Although hallucinogens are relatively safe physiologically and are not considered drugs of dependence, their administration involves unique psychological risks. The most likely risk is overwhelming distress during drug action ('bad trip'), which could lead to potentially dangerous behaviour such as leaving the study site. Less common are prolonged psychoses triggered by hallucinogens. Safeguards against these risks include the exclusion of volunteers with personal or family history of psychotic disorders or other severe psychiatric disorders, establishing trust and rapport between session monitors and volunteer before the session, careful volunteer preparation, a safe physical session environment and interpersonal support from at least two study monitors during the session. Investigators should probe for the relatively rare hallucinogen persisting perception disorder in follow-up contact. Persisting adverse reactions are rare when research is conducted along these guidelines. Incautious research may jeopardize participant safety and future research. However, carefully conducted research may inform the treatment of psychiatric disorders, and may lead to advances in basic science.