Selection Bias in Psychedelic Research: Comparing Self-Reported Quality-Of-Life Impact Between Enthusiasts and a General Population Sample

People who are enthusiastic about psychedelics report greater improvements in quality of life from their experiences compared to a general population sample, even after accounting for differences in mindset, setting, motivation, and personality. The study surveyed 1,182 participants (583 enthusiasts and 599 general population) with prior psychedelic use. Enthusiasts scored higher on openness, extraversion, and agreeableness, had more favorable mindsets and settings, and were more motivated by personal growth. Sample membership was the strongest predictor of reported quality-of-life impact, followed by setting, motivation, openness, and mindset. These results clarify how recruiting enthusiasts can inflate reported benefits and highlight the need for representative sampling in psychedelic research.

Study at a glance

Abstract

Psychedelic experiences have been associated with improved quality of life, but many studies rely on samples of enthusiasts, raising concerns about selection bias. This study examined whether self-reported quality-of-life impact differed between a convenience sample of psychedelic enthusiasts and a general population sample recruited through Prolific, and whether sample differences persisted after controlling for mindset, setting, motivation, and personality. A total of N = 1,182 participants (N = 583 enthusiasts; N = 599 general sample) with prior psychedelic experience completed an online survey assessing perceived impact, contextual factors, motivation for use, and Big Five personality. Between-group differences were analyzed using Welch’s t-tests, Pearson´s chi-squared tests and Mann-Whitney-Wilcoxon tests. A Type III ANCOVA was used to assess whether sample differences in quality-of-life impact remained after controlling for relevant covariates. Enthusiasts reported significantly greater quality-of-life impact (d = 0.84), higher openness, extraversion and agreeableness, more favorable mindsets and settings, and a higher frequency of personal growth motives. In the ANCOVA, sample membership was the strongest predictor of quality-of-life impact, followed by setting, motivation, openness, and mindset. These findings provide empirical clarification of how enthusiast-leaning recruitment strategies can shape reported outcomes in psychedelic research. Results underscore the need to consider sampling frames when interpreting reported benefits and to prioritize representative recruitment in future psychedelic research.