Of Roots and Fruits A Comparison of Psychedelic and Nonpsychedelic Mystical Experiences

Yaden and colleagues frame the study within a longstanding theoretical debate about whether the origins of religious, spiritual, or mystical experiences (RSMEs) matter for their value. Earlier work, notably William James's pragmatism, argues that the worth of such experiences should be judged by their outcomes or "fruits" rather than their physiological or situational causes or "roots." That debate has resurfaced in the context of psychedelic substances, which reliably occasion RSMEs in both laboratory and naturalistic settings; some scholars claim psychedelically induced experiences are essentially the same as spontaneous mystical experiences, while others argue they are qualitatively different or less authentic. This paper sets out to provide empirical data to address that question. Using an online survey, the investigators compared self-reported RSMEs that participants identified as psychedelically induced with those attributed to nonpsychedelic triggers. They hypothesised there would be nonsignificant differences between the two groups on (a) mystical quality, (b) positive impact across domains including family, fear of death, health, and sense of purpose, and (c) religiosity and spirituality, thereby testing whether the "roots" (origin) influence the "fruits" (outcomes) of RSMEs.

The study used a cross-sectional, self-report design based on an online survey hosted by the University of Pennsylvania; institutional review board approval was obtained. The analyzed data set comprised 739 participants drawn from an original 839 respondents after excluding 100 cases with incomplete data on measures of interest. The sample demographics reported included a majority White/Caucasian composition (82.8%), predominantly middle class (76.2%), and an unusually high proportion of self-identified atheists (25%). The extracted text does not clearly report recruitment details beyond the online posting and the fact that the survey advertised itself as exploring religious and spiritual experiences. RSMEs were evaluated with a subset of items from the larger survey. Mystical experience was measured using the five-item mystical experience subscale of the Death Transcendence Scale, which is based on Hood's Mysticism Scale; internal consistency in this sample was excellent (α = .90). Classification of an RSME as psychedelically induced relied on two survey items asking which substances the participant had ever taken and whether that substance had affected their spiritual or religious experience; a participant was placed in the psychedelic-triggered group only if they reported lifetime use of hallucinogens and affirmed that such substances influenced their RSME. Impact of the RSME was assessed via six single-item questions (family, reduced fear of death, health, sense of purpose, religiousness, spirituality) scored on 5-point scales; these items were analysed separately and as an averaged composite (α = .71). For statistical analyses, Spearman correlations and chi-square tests compared demographics between psychedelic and nonpsychedelic groups. Primary outcome comparisons used analyses of covariance (ANCOVAs) predicting mystical experience and RSME impact while controlling for gender, socioeconomic status, education, and religious affiliation (Christian versus other). Secondary ANCOVAs examined associations between mystical experience and use of other classes of substances (e.g., opiates, party drugs, antidepressants). The extracted text does not provide additional procedural detail such as survey timing or failure rates for specific items.

After exclusions for incomplete data, 739 participants were included in the analyses; 347 indicated their most impactful RSME was psychedelically induced and 392 indicated a nonpsychedelic trigger. The excluded 100 respondents differed modestly from included participants: excluded cases were less likely to be atheists or to identify with some other religions and included participants scored higher on the Mysticism Scale (mean 3.22 vs 3.03, t(837) = 3.28, p = .001, d = .20). Demographic contrasts between groups were notable. The psychedelic-triggered group comprised a higher proportion of males (reported as 72.3% vs. 32.7% in the nonpsychedelic group), fewer self-identified Christians (7.2% vs. 32.7%), and a greater proportion in "other" religious categories (54.2% vs. 39.5%). Psychedelic use was inversely related to education and socioeconomic status. These baseline differences were taken into account in adjusted analyses. On primary outcomes, experiences attributed to psychedelic substances were rated higher in mystical quality (effect size d = .75, p < .001). Psychedelic-triggered RSMEs also showed greater positive impact in specific domains: reduced fear of death (d = .21, p < .01), increased sense of purpose (d = .18, p < .05), and increased spirituality (d = .28, p < .001), compared with nonpsychedelic RSMEs. ANCOVAs controlling for gender, SES, education, and Christian affiliation confirmed that the psychedelic group scored higher on mystical experience and on the composite RSME impact measure. Secondary analyses examined non-psychedelic pharmacological influences: after the same covariate adjustments, opiate use and "party drug" use showed a small but statistically significant association with mystical experience (both p < .01, ηp2 = .02), whereas antidepressants, psychiatric medications, sedatives, and antianxiety medications were not associated (ps > .10). The extracted text does not provide full ANCOVA tables, confidence intervals, or longitudinal outcomes.

Contrary to their initial hypotheses of no meaningful differences, the investigators found that psychedelically occasioned RSMEs were rated as more intensely mystical and as having greater existential and spiritual impact than RSMEs arising through other means. The largest between-group difference concerned the mysticism dimension, which in this study emphasises feelings of unity; the authors suggest this may reflect the characteristic visceral and sensory alterations that many psychedelics reliably produce. Placing the findings in broader context, the paper notes consistency with laboratory studies showing enduring meaningfulness and positive behavioural outcomes following psychedelic sessions. The authors also reference epidemiological work suggesting lifetime psychedelic use is not associated with increased psychological distress and may be protective against suicidality, and they comment on emerging evidence for antidepressant effects. Nevertheless, they emphasise that the present results address only subjective positive feelings and that no conclusions can be drawn here about other outcomes such as physical health or psychological harm. Several limitations acknowledged by the authors temper interpretation. The sample was nonrepresentative and subject to self-selection bias: the survey explicitly solicited people with RSMEs, and the sample contained an unusually high proportion of atheists and fewer Christians than the general U.S. population. The cross-sectional, self-report design prevents causal inference; for example, the data cannot determine whether a greater propensity to mystical experiences led to psychedelic use or vice versa. Measurement of whether an RSME was psychedelically induced was coarse—the classification required lifetime use of hallucinogens plus a self-report that a substance influenced the RSME—so some nonpsychedelic pharmacological influences could have been missed or conflated. Group differences in demographics (education, SES, religiosity, gender) present potential confounds despite statistical adjustment. Regarding implications, the authors recommend further experimental and longitudinal research, including randomised controlled trials, to clarify causality and moderators such as religious, spiritual, and secular interpretations. They also suggest that other nonpharmacological methods for eliciting intense experiences (meditation, ritual, noninvasive brain stimulation) warrant empirical comparison. While the authors tentatively note supervised psychedelic sessions as a potential intervention to enhance wellbeing or treat clinical conditions, they stress the importance of responsible use, regulation, and supportive therapeutic context.

Invoking William James's pragmatism, the authors conclude that psychedelic-triggered RSMEs should be judged by their outcomes rather than dismissed because of their physiological occasion. Their data indicate that, on average, psychedelically induced experiences can match or exceed the intensity and perceived impact of RSMEs arising through nonpsychedelic means, challenging assumptions that such experiences are inherently less genuine or beneficial.