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Randomized Controlled Trial
. 2012;7(2):e30800.
doi: 10.1371/journal.pone.0030800. Epub 2012 Feb 17.

Prediction of psilocybin response in healthy volunteers

Erich Studerus  1 , Alex Gamma, Michael Kometer, Franz X Vollenweider
Affiliations
Randomized Controlled Trial

Prediction of psilocybin response in healthy volunteers

Erich Studerus et al. PLoS One. 2012.

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.

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Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. Regression coefficients of the final models pooled across 20 imputed data sets.
The effects are adjusted for the influences of all other variables in the models. One, two, and three asterisks represent p-values formula image0.05, 0.01, and 0.001, respectively.
See this image and copyright information in PMC

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