Reduced death anxiety and obsessive beliefs as mediators of the therapeutic effects of psychedelics on obsessive compulsive disorder symptomology

Interest in clinical applications of psychedelics has resurged over recent decades, with accumulating evidence that psychedelic experiences can produce lasting improvements in subjective well-being. However, the psychological mechanisms that might explain these longer-term benefits remain poorly understood, and much work has concentrated on clinical trials rather than naturalistic use. One putative pathway that has received relatively little empirical attention is reductions in death anxiety: previous studies have reported decreases in fear of death following psychedelic-assisted interventions for terminal illness and in healthy samples, and theoretical accounts link psychedelic-induced ‘‘ego‑death’’ or unity experiences to attenuated death fears. Moreton and colleagues set out to examine whether reductions in death anxiety could mediate the relationship between acute subjective effects of a meaningful psychedelic experience (specifically mystical-type experiences and psychological insight) and retrospective changes in subjective well-being. The study tested a series of hypotheses: that well-being would increase and death anxiety decrease from before the chosen experience to the present; that mystical and insight experiences would predict improvements in well-being and reductions in death anxiety; and that decreases in death anxiety would mediate the effects of mystical experience and psychological insight on well-being.

This was a retrospective, cross-sectional online survey of adults who reported a personally meaningful psychedelic experience. Recruitment occurred via targeted social media advertisements (Facebook and Reddit groups focused on psychedelics). Inclusion criteria were age 18 or over, fluency in English, and having taken at least one psychedelic (e.g. LSD, DMT, ayahuasca, mescaline, psilocybin) that evoked a meaningful experience. Data were collected between 15 June 2020 and 3 September 2020 and the University of Wollongong Human Research Ethics Committee approved the procedures. From 656 visitors, 527 provided consent. After excluding 284 participants for incomplete surveys, seven for failing an attention check, and 35 for reporting the meaningful experience either within the past week or more than ten years ago, the final sample comprised 201 participants. Participants first provided demographics, then identified a particularly meaningful psychedelic episode and completed measures about that acute experience. They then provided retrospective ratings of how they were before the experience (T1) and current ratings of how they are now (T2). Participants could enter a draw for one of two AU$100 vouchers. Acute-experience measures comprised the Mystical Experience Questionnaire-30 (MEQ-30; total mean score used) and the Psychological Insight Questionnaire (PIQ; mean of 28 items). Retrospective pre/post measures included the Satisfaction with Life Scale (SWLS) for cognitive well-being, the Scale of Positive and Negative Experience (SPANE) for affective well-being (positive and negative affect subscales), and the Death Attitude Profile–Revised Fear of Death subscale (DAP-R) for death anxiety. Internal consistency (Cronbach’s alpha) was reported as good to excellent across measures (e.g. MEQ30 a = .92; PIQ a = .95; DAP-R a's = .92; SWLS pre a = .89, post a = .87). Analyses involved descriptive reporting of change direction, four repeated-measures ANOVAs comparing pre and current scores, bivariate correlations among acute effects and change scores, and mediation testing using Hayes’ PROCESS Model 4 with 5,000 bootstrap samples to test indirect effects of mystical experience and psychological insight on three well-being outcomes via changes in fear of death. Mystical experience and psychological insight were alternately entered as independent variable and covariate to examine unique effects. Non-standardised regression coefficients and 95% bootstrap confidence intervals were reported for indirect effects.

Sample demographics reported a mean age of 32.90 years (SD = 11.47); gender counts were 116 male, 78 female, six another gender, and one who preferred not to say. High attrition occurred between initial consent and final sample (527 consented; 201 retained for analysis). In terms of directional change, 87.06% of participants reported increased life satisfaction, 79.60% reported increased positive affect, 81.01% reported decreased negative affect, and 79.10% reported decreased death anxiety from before the chosen psychedelic experience to the present. Repeated-measures ANOVAs showed significant mean improvements on all outcomes. For example, the average summed SWLS score shifted from 19.44 (‘‘Slightly dissatisfied’’ range) at T1 to 29.70 (‘‘Satisfied’’ range) at T2. Bivariate correlations indicated a moderate positive association between mystical experience (MEQ-30) and psychological insight (PIQ). Mystical experience showed small-to-moderate correlations with increases in well-being (all measures) and with decreases in fear of death. Psychological insight was moderately correlated with improvements in well-being but did not correlate significantly with changes in death anxiety. Mediation analyses (six models: mystical/insight × three well-being outcomes) using PROCESS with 5,000 bootstrapped samples found significant indirect effects of mystical experience on satisfaction with life, positive affect, and negative affect via reductions in fear of death. By contrast, there were no significant indirect effects of psychological insight operating through death anxiety. When mystical experience and psychological insight were included together in predictive models, psychological insight emerged as the stronger direct predictor of changes in well-being, whereas mystical experience—but not psychological insight—predicted reductions in death anxiety.

Moreton and colleagues interpreted the findings as largely consistent with their hypotheses: retrospective reports indicated increases in subjective well-being and decreases in death anxiety following the self‑identified meaningful psychedelic experiences, and both mystical experience and psychological insight were associated with improved well-being. The observation that psychological insight was the stronger direct predictor of well-being when both predictors were modelled together was highlighted as notable, and mystical experience uniquely predicted reductions in death anxiety. Crucially, reductions in death anxiety significantly mediated the relationship between mystical experience and improvements in well-being, providing partial support for the authors’ proposal that attenuated death fears could be one mechanism linking certain psychedelic experiences to enhanced well-being. The authors noted that psychological insight—as measured by the PIQ—did not predict reduced death anxiety; they suggested this may reflect the PIQ’s content domain, which emphasises interpersonal and cognitive–behavioural insights rather than metaphysical or ultimate‑meaning insights that might be more relevant to attitudes toward death. Several limitations acknowledged by the authors temper causal inference. The retrospective cross‑sectional design permits alternative interpretations, including reverse causality or confounding by unmeasured factors (for example, changes in connectedness or meaning in life). Recall bias is a concern given variable elapsed time since the chosen experience, and the self‑selected sample likely overrepresents individuals who appraise psychedelic experiences as meaningful. High attrition could induce non-random bias, and the final sample size limited power to detect small associations. The authors therefore call for prospective, controlled research to determine how frequently psychedelics reduce death anxiety, how long such effects persist, and the psychological pathways involved. They also recommend development of broader measures of insight (including metaphysical and spiritual domains) and consideration of eudaimonic forms of well-being in future studies.

The study found that reductions in death anxiety mediated the relationship between psychedelic‑induced mystical experiences and retrospective improvements in subjective well-being. Although the design was retrospective and cannot establish causality, the results provide preliminary evidence that attenuated death fears may be one pathway through which certain psychedelic experiences confer longer‑term benefits. The authors conclude that these findings justify further prospective and mechanistic research into death anxiety as a potential mediator of psychedelics’ therapeutic effects, and into for whom and under what conditions such effects are most likely to occur.