Table 1.
Differences in participant characteristics, set and setting.
| Study | Substance | Dose | Age | Sample population | Prior experience | Intentions | Setting |
|---|---|---|---|---|---|---|---|
| Soler et al. (56) | Ayahuasca | 28.82–69.81 mg DMT | 43.6 ± 12 | Healthy, highly educated | 92% Aya-huasca (1–500 times) | • Self-knowledge • Introspection | • Non-religious; dimly-lit room with pre-recorded music • Naturalistic study; experimenters present before, during and after session |
| Sampedro et al. (57) | Ayahuasca | 0.64 mg DMT/kg | 38.9 ± 7.8 | Healthy, highly educated | 100% (62 ± 99 times) | • Personal growth • Introspection |
• Non-religious; dimly-lit room; silence alternated with pre-recorded music • Naturalistic study; experimenters present before, during and after session |
| Soler et al. (52) | Ayahuasca | N.R. | 50 ± 14.7 | Healthy | 100% Ayahuasca | • Self-knowledge • Introspection |
• Non-religious; dimly-lit room with pre-recorded music • Naturalistic study; experimenters present before, during and after session |
| Uthaug et al. (58) | Ayahuasca | 189.4–915.4 mg DMT | N.R. | 60% Healthy12% Depression1% Anxiety0.04% Personality Disorder0.02% Addiction | 57% Ayahuasca; 70.4% Psy | • Self-understanding • Solving issues • Curiosity |
• Non-religious; traditional S. American music played; at night • Led by experienced shamans who provided support if needed + ≥2 ayahuasca facilitators • Dutch sample: tipi/big hotel room • Colombian sample: rainforest location/dimly-lit maloca (ceremonial building) |
| Uthaug et al. (40) | 5-MeO-DMT (from Bufo alvarius) | 20–120 mg | 38 ± 5.2 | 76.2% Healthy9.4% Anxiety7.1% Addiction2.4% Depression2.4% Personality disorder | 80% 5-MeO-DMT; 92.9% Psy | • Self- understanding • Solving issues • Healing/trans-formation • Spiritual growth • Find one's purpose |
• Non-religious; traditional S. American music played • Sessions led by experienced facilitators and assistants who provided help with integration if needed • Dutch + Czech sample: garden/secluded natural location • Spanish sample: in tipi/rented house |
| Uthaug et al. (59) | 5-MeO-DMT (synthetic) | 15–61 mg | 33 ± 8.6 | Healthy, highly educated | 18% 5-MeO-DMT; 100% Psy | • Self-understanding • Curiosity • Solving problems • Explore possibilities |
• Individualised 1-to-1 sessions at yoga studio • Held by trained facilitator |
| Griffiths et al. (60) | Psilocybin | 20 + 30 mg/70 kg | 42 ± 10.6 | Healthy, highly educated | 25% Psy | • Exploring spiritual life • Curiosity |
• Lying on couch in aesthetic living-room-like envi-ronment; wearing eye mask and headphones playing classical/world music • Supportive but nondirective guides • 1-month preparation and spiritual training with guide; opportunity for integration (and group discussion sessions in the high support group) |
| Smigielski et al. (61) | Psilocybin | 315 μg/kg | 52.8 ± 2.5 | Healthy meditators, highly educated | 45% Psy | N.R. | • Within silent Zen meditation retreat, during block of sitting meditation; musical elements and relaxation periods during acute effects |
Summary of different participant characteristics and conditions used in the studies reviewed in the main text. For controlled studies, participant characteristics and conditions are listed for the experimental group, where a (active dose of a) psychedelic was administered. Prior experience is listed in terms of percentage of participants who had previous experience with the psychedelic used in the respective study, and also includes percentage of participants with prior experience of other psychedelics (Psy), where the first number is not 100%. (N.R., Not reported).