Psychedelic use and intimate partner violence

The relationship between substance use and violent behaviour has been widely studied, with strong evidence linking alcohol, methamphetamine, cocaine and PCP to increased aggression. In contrast, the literature on hallucinogens and aggression is mixed: earlier studies report both risk and protective associations, while more recent reviews and longitudinal work suggest that classic psychedelics (compounds acting primarily as 5-HT2A agonists such as LSD and psilocybin) may be associated with reduced antisocial behaviour. Psychedelic experiences are heterogeneous and can produce acute anxiety or rare adverse reactions, but contemporary clinical and observational studies have also reported salutary effects on internalising disorders and on some externalising outcomes such as problematic substance use and criminality. St and colleagues designed the present study to test whether lifetime use of LSD and/or psilocybin mushrooms is associated with perpetration of intimate partner violence (IPV) in a community sample, and whether emotion regulation might mediate any observed association. The investigators hypothesised that prior psychedelic use would be linked to lower odds of IPV perpetration, that psychedelic users would report better emotion regulation, and that emotion regulation would at least partly explain the relationship between psychedelic use and reduced IPV. The study therefore aimed to extend prior findings from correctional samples to a broader community population and to explore a plausible psychological mechanism for any protective effect.

Participants were 1,266 adults recruited from two Canadian universities (The University of British Columbia, n=742; Laurentian University, n=302) and two online sources (Reddit subforums related to psychedelics, n=122; Amazon Mechanical Turk, n=100). The sample ranged from 16 to 70 years (mean=22.78, SD=7.71) and was 61.77% female. University participants received course credit, Reddit respondents were entered into a gift-card draw, and AMT participants received monetary compensation. Ethics approval was obtained from both universities. Lifetime psychedelic use was measured for LSD and psilocybin on a five-point frequency scale; responses were dichotomised so that any report of one or more uses qualified a respondent as a psychedelic user. Emotion regulation was assessed with the 36-item Difficulties in Emotion Regulation Scale (DERS), which yields a total score where higher values indicate greater difficulties across domains such as awareness, clarity, acceptance, access to strategies, goal-directed behaviour and impulse control. Intimate partner violence was measured using the revised short-form Conflict Tactics Scale (CTS2S); a dichotomous variable captured past-year physical assault if participants endorsed one or more items from the Physical Assault subscale (examples: pushing, slapping; punching, kicking, beating up). Alcohol use was measured with the 10-item Alcohol Use Disorders Identification Test (AUDIT) and included as a covariate due to its known association with violence. Analyses began with chi-square tests and Pearson/point-biserial correlations to examine bivariate relationships and sample differences. Binary logistic regression models tested the association between lifetime psychedelic use and IPV while controlling for alcohol use. Mediation was tested using the PROCESS macro in SPSS with bootstrapping (5,000 samples) to estimate indirect effects; the Sobel test was also reported. Because of established gender differences in IPV, the investigators ran analyses on the combined sample and separately by gender. Where necessary, missing DERS items (<20% missing per case) were prorated to compute total scores; less than 1% of DERS data required this estimation.

Initial comparisons found no differences between the two university samples in rates of psychedelic use (χ2=0.79, p=0.38) or IPV (χ2=0.19, p=0.67). Among the online sources there were no differences in IPV rates (χ2=1.99, p=0.16) but there were differences in psychedelic use (χ2=48.23, p<0.05). Given similarities in recruitment, the four source groups were collapsed into a university sample and an online sample. The online sample showed higher rates of past psychedelic use (collapsed-sample difference χ2=233.75, p<0.01) but the two collapsed samples did not differ in IPV rates (χ2=1.22, p=0.27). Overall, 404 participants (31.9%) reported lifetime use of LSD and/or psilocybin. Past-year IPV perpetration was reported by 141 participants (11.10%). Bivariate correlations indicated that alcohol use was positively associated with both IPV and psychedelic use for both sexes, and that greater emotional dysregulation was associated with higher IPV across genders. Psychedelic use was associated with fewer difficulties in emotion regulation among males only. Emotional dysregulation correlated with more problematic alcohol use among females only. Binary logistic regression controlling for alcohol use found an inverse relationship between lifetime psychedelic use and IPV perpetration. A significant gender-by-psychedelic-use interaction indicated that the inverse association was present among males but not females, and no interaction was found between psychedelic use and sample type; therefore subsequent analyses combined samples. In the male-only mediation analyses (n=484) the investigators residualised psychedelic use after adjusting for AUDIT scores and standardised variables for interpretation. Psychedelic users showed fewer difficulties with emotion regulation (b=-0.12, SE=0.05, p<0.05). Those who perpetrated IPV had greater emotion-regulation difficulties (b=0.19, SE=0.05, p<0.01). The direct negative association between psychedelic use and IPV was b=-0.11 (SE=0.04, p<0.05) and was reduced to b=-0.09 (SE=0.04, p>0.05) after adding emotion regulation to the model, consistent with mediation. The Sobel test supported a mediating effect of emotion regulation (Z=-2.17, p<0.05). The authors also note that men endorsing lifetime psychedelic use reported roughly half the rate of past-year IPV compared with non-users (5.1% vs 10.0%).

St and colleagues interpret their findings as preliminary evidence that a history of LSD and/or psilocybin use is associated with a lower likelihood of perpetrating physical intimate partner violence among men in a community sample. The magnitude of the association was notable: men who reported lifetime psychedelic use were about half as likely to report past-year physical IPV as men who had never used these substances. The direction and magnitude are consistent with prior longitudinal work in correctional populations, suggesting the negative relationship may generalise beyond incarcerated samples. Emotion regulation emerged as a partial mediator, which the investigators argue supports a plausible psychological mechanism: prior psychedelic experience was associated with fewer difficulties in emotion regulation, and better emotion regulation in turn related to lower IPV perpetration. The authors link this mediation to experimental findings that psilocybin can modulate emotional processing and to theoretical proposals that psychedelics may foster mindfulness, emotional integration and psychological flexibility. They caution that the observed gender difference — an association present in men but not women — may reflect differences in the function of partner violence; for example, female-perpetrated IPV is more likely to be defensive, which might not be influenced by the processes engaged by psychedelic use. Alcohol use remained associated with IPV and the investigators note the importance of controlling for alcohol and other substances when studying links between psychedelics and antisocial behaviour. Key limitations acknowledged by the authors include the cross-sectional design, which precludes causal inference; potential confounding by unmeasured personality or other individual differences that predispose both to psychedelic use and lower violence; and reliance on self-report measures for substance use and IPV, which are vulnerable to reporting bias. The study's strengths included a relatively large sample, detailed measurement of psychedelic use, and a theoretically driven analytic approach. The authors conclude that their results provide further preliminary evidence of an inverse relationship between psychedelic use and violence among men and recommend further research into whether psychedelic therapies might reduce interpersonal violence, while emphasising the need for studies that can address causality and underlying mechanisms.