Motives for the use of serotonergic psychedelics: A systematic review

Psychoactive substances are used for many different reasons, and research on substance-use motives has developed models to explain why people use particular drugs. Based on motivational work in alcohol and cannabis research, a five-factor model of substance-use motives is often employed: social, conformity, coping, enhancement and expansion. The expansion motive—reflecting a wish to gain self-knowledge or alter perception—was added to capture motives more typical of substances with psychedelic properties. This review by Basedow and colleagues set out to fill a gap: no prior synthesised review had characterised motives for use specifically across the class of serotonergic psychedelics (SPs), which include tryptamines (for example psilocybin, DMT), ergolines (for example LSD) and phenethylamines (for example mescaline). The study aimed to summarise which motives have been assessed in the literature, compare findings from quantitative versus qualitative studies, and explore whether reported motives vary by year of publication, specific SPs, or participant populations. The investigators anticipated that qualitative and quantitative approaches might yield different frequencies of reported motives.

The investigators conducted a systematic review reported according to PRISMA. Electronic searches were run in Medline, Web of Science and Embase from database inception to 5 November 2020, using search terms linking a selection of SPs and terms associated with use motives. References from review articles were hand-searched. The review was not registered. Studies were eligible if they were peer-reviewed, written in English, German, Spanish or Dutch, included at least one human participant, and explicitly assessed motivations or reasons for SP use. Initial screening proceeded by language, journal and title, followed by abstract screening and full-text assessment where applicable. Screening was performed independently by two researchers (LAB, SKP). From each eligible article the first author recorded bibliographic details, the SP(s) investigated and whether the study used a qualitative or quantitative approach. Extracted motive data were mapped onto the five standard motive dimensions (conformity, coping, enhancement, expansion and social). For each study, the presence or absence of each motive was coded as 1 or 0. Data underlying the review were made available in the paper’s supporting information. To test whether report type (qualitative versus quantitative) was associated with differing proportions of motives, odds ratios were calculated; the authors interpreted odds ratios using conventional thresholds for small, medium and large effects. Binary logistic regressions examined whether year of publication predicted the presence of each motive (year entered as a continuous predictor). The investigators planned χ2 tests to compare motive proportions across participant populations and specific SPs, but the small number of studies precluded these analyses. Statistical significance was set at alpha <0.05 and effect-size conventions from Cohen were used.

The search screened 30,257 unique records, of which 113 underwent full-text assessment and 37 studies met inclusion criteria. Slightly more than half of included studies used qualitative methods (n = 20, 54%), while 17 studies (46%) used quantitative methods. The qualitative studies together covered more than 1,372 participants overall, whereas quantitative studies covered a larger aggregated sample (n = 11,452). The median year of publication for qualitative studies was 2010, and for quantitative studies 2016. Across the 37 included studies the expansion motive emerged as the most prominent reason reported for SP use. Over half of the studies also reported coping and enhancement motives, whereas social and conformity motives were rarely reported. When comparing report types, odds ratios for the presence of particular motives did not reach statistical significance (all P > 0.05), although the odds ratios for coping and enhancement met thresholds interpreted as small effects. Year of publication was not significantly associated with the presence of any of the five motives. Planned χ2 comparisons across user populations (for example patients, ritual contexts, prisoners) and across specific SPs (for example LSD, tryptamines, mescaline) were not possible because too few studies addressed these categories. Where studies focused on particular populations, social and conformity motives were not reported in ritualised use contexts, and the single prison study did not report coping motives. In the subset of studies addressing a single SP, none reported conformity motives. Qualitative analyses yielded two broader themes that did not map cleanly onto the five-factor model. First, several accounts framed SP use as a form of identity or cultural belonging (for example, descriptions of drug use as expressing ‘‘otherness’’ or subcultural values). Second, participants sometimes described using SPs to gain or explore spiritual or extraordinary powers; reported aims ranged from accessing hidden knowledge to ambitions expressed as becoming ‘‘a god’’ while using ayahuasca. A few unique motivations were reported in single studies, such as intuitive, spontaneous decision-making and using SPs as preparation for therapeutic work.

Basedow and colleagues interpret their findings as indicating that expansion is the dominant motive for SP use across time, contexts and substances. They note that while coping and enhancement motives appeared in more than half of studies, the social and conformity motives that characterise other substances were infrequently reported for SPs. The predominance of expansion aligns with the motive’s conceptual origin in research on substances that produce perceptual and self‑reflective effects. Contrary to the authors’ expectation, qualitative and quantitative study types did not differ significantly in the proportions of motives they reported. A small, non-significant tendency for qualitative studies to report coping motives more often than quantitative surveys was observed; the investigators suggest this could reflect questionnaire wording (structured coping items may be framed too broadly), greater opportunity to elaborate on specific negative states in interviews, or reduced social desirability effects once rapport is established in qualitative interviews. The relative stability of motives across publication year, SP type and participant population led the authors to conclude that motives for SP use are remarkably similar across contexts, supporting the idea of SPs as a coherent substance class despite pharmacological differences among members. The authors acknowledge several limitations. Foremost, applying a top-down five-factor model to qualitative data constrains interpretation and requires subjective mapping of open-ended responses into predetermined categories; reproducibility of that mapping is uncertain. They did not perform a formal risk-of-bias assessment across included studies and analysed motive occurrence at the study rather than the participant level, which precluded controlling for sample characteristics such as age, gender, co-occurring substance use or mental disorders. The review also focused on trait motives reported retrospectively; no ecological momentary assessment studies of SP motives were identified. Finally, the authors highlight that some motives—such as desires for magical powers or identity-related reasons—are not captured by the five-factor framework and warrant attention in future work. From these findings the investigators derive practical implications: standard quantitative instruments appear to capture the common motive structure for SP users, but future surveys should allow respondents to add and rate individual or rare motives. They also recommend more research analysing motives for specific SPs. In harm-reduction and prevention settings, the authors suggest that providing non-pharmacological practices that satisfy an expansion motive (for example meditation or breathwork) might reduce the degree to which people seek psychedelic experiences pharmacologically. In clinical settings, the prevalence of expansion- and insight-seeking motives is noted as consistent with contemporary interest in SP-assisted psychotherapy for affective disorders.

The review concludes that across diverse user populations, including psychiatric patients, SPs are most often used to expand self-knowledge, promote spiritual development or satisfy curiosity. Standardised instruments capture these common motives, but some unique motivations reported in qualitative work fall outside the five-factor model and merit further study.