Prediction of Psilocybin Response in Healthy Volunteers
PLoS ONE – February 17, 2012
Source: OpenAlex
Summary
Drug dose is crucial, yet non-pharmacological factors significantly shape responses to the hallucinogen psilocybin. Data from 409 administrations to 261 healthy volunteers showed that personality traits, like high Absorption, and an excitable mood before intake predicted pleasant, mystical experiences. Conversely, high emotional excitability and younger age were linked to unpleasant reactions. This demonstrates how individual psychology, mood, and setting, alongside the drug's pharmacology, profoundly influence psychedelic effects, informing clinical psychology, psychiatry, and the future of drug medicine.
Abstract
Responses to hallucinogenic drugs, such as psilocybin, are believed to be critically dependent on the user's personality, current mood state, drug pre-experiences, expectancies, and social and environmental variables. However, little is known about the order of importance of these variables and their effect sizes in comparison to drug dose. Hence, this study investigated the effects of 24 predictor variables, including age, sex, education, personality traits, drug pre-experience, mental state before drug intake, experimental setting, and drug dose on the acute response to psilocybin. The analysis was based on the pooled data of 23 controlled experimental studies involving 409 psilocybin administrations to 261 healthy volunteers. Multiple linear mixed effects models were fitted for each of 15 response variables. Although drug dose was clearly the most important predictor for all measured response variables, several non-pharmacological variables significantly contributed to the effects of psilocybin. Specifically, having a high score in the personality trait of Absorption, being in an emotionally excitable and active state immediately before drug intake, and having experienced few psychological problems in past weeks were most strongly associated with pleasant and mystical-type experiences, whereas high Emotional Excitability, low age, and an experimental setting involving positron emission tomography most strongly predicted unpleasant and/or anxious reactions to psilocybin. The results confirm that non-pharmacological variables play an important role in the effects of psilocybin.