Quality of reporting on psychological interventions in psychedelic treatments: a systematic review

Data extraction and rating were performed from the included articles, treatment protocols, and supplementary materials when available. Three extractors (CS, NS, and LS) collected predefined information about study design, sample size, diagnostic indication, psychedelic substance and dose, route of administration, number and timing of dosing sessions (pre-dosing, dosing, post-dosing), treatment denomination and duration, setting, descriptions of the psychological intervention, therapist background and whether therapists received intervention-specific training, plus descriptive details about preparatory, dosing, and integration sessions and monitoring. AJOM intervened when extractors disagreed. When multiple sources existed (for example, article and manual), the most detailed source was used where inconsistencies occurred. The authors prioritised reporting of established psychotherapies over novel adjunct procedures when both were described. Completeness of reporting was evaluated using an adaptation of the Template for Intervention Description and Replication (TIDieR) checklist. Each of the 12 TIDieR items (denomination, rationale, materials, procedures, provider, modality, location, frequency, tailoring, modification, adherence measures, and adherence reporting) was scored 1 if present or 0 if absent, yielding total scores from 0 to 12 where higher scores indicate more complete reporting. Two raters (BSB and Dd'O) applied the adapted checklist independently and resolved disagreements by consensus with CS intervening if needed. For analysis, TIDieR scores were summarised with means and standard deviations and stratified by psychedelic substance, study design, and publication date.

Forty-five studies were included in the review, representing 1,464 participants treated with psilocybin (21 studies), MDMA (11), dimethyltryptamine or ayahuasca (9), and LSD (4). Indications covered a wide range: PTSD (11 studies), major depressive disorder (8), treatment-resistant depression (6), cancer-related anxiety or depression (5), substance use disorders (4), alcohol use disorder (3), and single studies for personality disorder, bipolar II, anorexia nervosa, body dysmorphic disorder, illness-related anxiety/depression, obsessive–compulsive disorder, social anxiety in autism spectrum disorder, and tobacco addiction. Therapy manuals were referenced in some studies: nine MDMA and seven psilocybin papers mentioned manuals, but only two manuals were available for inspection. All MDMA studies that reported a manual referenced the same MAPS (Multidisciplinary Association for Psychedelic Studies) treatment manual; for psilocybin, only one accessible manual could be obtained for a single study. No LSD or dimethyltryptamine/ayahuasca studies cited an accessible manual. Psilocybin studies uniformly implemented individual psychotherapy (two also offered group sessions). The reported number of sessions ranged from three to 20, and treatment durations (reported in most studies) varied from about 2 to 37 weeks. Most protocols used three phases—preparatory sessions, one or more dosing sessions (typically one or two), and integration sessions—often taking place in living-room-like settings and commonly using standardised music playlists. Preparatory work tended to include psychoeducation and rapport-building, sometimes incorporating visualisation, relaxation, body scan or guided imagery. Therapist background was frequently not reported (eight studies omitted it), though psilocybin-specific training was noted in 12 studies. Therapists were generally instructed to adopt an open, non-directive, minimally intervening stance during dosing sessions. The MDMA literature (11 trials, mostly for PTSD) typically described interventions more consistently. Treatment length ranged about 7–18 weeks and most trials used individual formats with co-therapist teams (often male–female pairs). Nearly all MDMA studies that referenced a manual pointed to the MAPS protocol, which emphasises non-directive, patient-centred support; some studies additionally reported use of CBT, dialectical behaviour therapy, mindfulness approaches, or motivational interviewing techniques. Preparatory sessions (2–4) were common, and dosing sessions featured living-room environments, eyeshades, headphones, and invitations to attend inwards. Up to four integration sessions were reported in some protocols; overnight stays after dosing were described in six studies. Information about therapist professional background was variably reported, and most MDMA studies referred readers to the MAPS manual for training details. LSD studies (four trials, some combined with MDMA) reported mixed approaches with both group and individual sessions. Two studies lacked preparatory sessions while others included psychoeducation and alliance-building; integration sessions were absent in two studies and present in others. Theoretical rationales were sparse overall, with one study referencing the structural dissociation model. Nine articles on dimethyltryptamine or ayahuasca mainly described ceremonial, often indigenous-influenced approaches for substance misuse, depression, and antisocial personality disorder; durations ranged from days to months. Most ayahuasca studies followed ceremonial formats with preparatory practices (for example, dietary restrictions, social isolation, purgative rituals) and group ceremonies led by traditional healers (ayahuasqueros or curanderos). Dosage and content were often unspecified (noted in five studies), and several studies did not conduct integration sessions. Monitoring and professional backgrounds varied and were frequently under-described. On the adapted TIDieR scale, the mean score across all 45 studies was 5.89 (SD 2.06), with scores ranging from 2 to 9. Psilocybin studies averaged 6.05 (SD 1.8) and LSD studies averaged 5. Item-level endorsement patterns varied by substance: procedures, modality, location, and frequency were universally endorsed for MDMA and LSD studies; MDMA-only studies also commonly endorsed denomination, procedure, and frequency. Psilocybin studies showed higher endorsement for procedure, modality, frequency, denomination, and provider. Dimethyltryptamine/ayahuasca studies had the lowest endorsement, with material, tailoring, modification, adherence, and adherence reporting not endorsed in any of those studies; these items were also poorly endorsed across other substances.

Seybert and colleagues interpret their findings as evidence that reporting on the psychological interventions accompanying psychedelic administrations is frequently incomplete and heterogeneous. Across psilocybin, MDMA, and LSD studies a common three-phase structure—preparation, support (dosing), and integration—could often be identified, but ayahuasca/dimethyltryptamine studies typically followed ceremonial protocols and lacked detailed descriptions of psychotherapeutic structure, content, therapist qualifications, and monitoring. The authors highlight that MDMA studies generally reported psychotherapeutic procedures more thoroughly, a pattern they link to widespread use of the MAPS treatment manual and a sponsor-driven standardisation that favours replicability. Adherence assessment tools were more often used in MDMA-assisted therapy, although actual adherence scores were seldom disclosed. Missing information about therapist professional background, training, and competency raises concerns regarding how these roles would be certified and regulated if treatments are approved for clinical use. The authors note that therapeutic alliance, despite its recognised importance in psychotherapy outcomes, has not been measured as an active component in the reviewed psychedelic trials. The review emphasises that, in current literature, the choice and adaptation of psychological interventions appear more influenced by the psychedelic substance and available manuals than by the patient diagnosis. This substance-oriented heterogeneity complicates efforts to disentangle the relative contributions of the drug versus the psychotherapeutic component to clinical outcomes. The authors therefore call for systematic process–outcome research that evaluates psychotherapy competencies, techniques, and therapist characteristics in the context of psychedelic trials, and for trials that compare different psychotherapeutic approaches or tailor them by diagnosis. Limitations acknowledged by the study team include lack of involvement of people with lived experience in the review process and incomplete access to underlying therapy manuals for several studies, which constrained assessment. Additionally, the TIDieR adaptation they applied—scored as a single total—was a novel approach in this field, preventing direct comparison with reporting quality in other psychotherapy research. Overall, the authors conclude that while reporting quality has shown slight improvement over time, persistent deficiencies in the description of psychotherapeutic components pose problems for interpretation of trial effects, reproducibility, clinician training, and patient safety, and they urge more thorough, standardised reporting and development of accessible treatment manuals.