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One-to-one, group, or couples: what has been reported

The question here is how sessions with one facilitator and one person, in a group and with a couple are described in published sources, and what is known about each. This card reports findings. It does not say which format suits anyone.

Published Information current to 7 November 2026Review due by 8 January 2027, before Oregon’s planned rule changes

Read this first. This page is education, not instructions to use. Metanoia does not supply any substance. In the United States, most of the substances discussed here are Schedule I under federal law (21 CFR 1308.11). State programs such as Oregon's and Colorado's operate under state law only, and federal law still applies. Legal status differs between countries, and none of this is legal advice. Nothing here is medical advice, and nothing here recommends a dose. Where an amount appears, it is the amount a study reports, not a suggestion. People who host, supply or take part in sessions involving controlled substances can face criminal liability under federal and state law. This page does not advise on that. "Healthy adults" means people with no diagnosed psychiatric or major medical condition, the population Metanoia studies. This page reports what published sources say about work done outside supervised programs, and it takes no position on the legality of any setting, practice or person.
Not an emergency resource. Metanoia is not an emergency service. In a medical or mental health emergency in the United States the number is 911, and the 988 Suicide and Crisis Lifeline is available by call or text. Elsewhere, local emergency numbers apply. Nothing on this card is a reason to delay or avoid care. This card describes what sources report. It is not a screening tool, it does not say who should take part in a session or in what setting, and it is not medical guidance. Metanoia does not receive or investigate complaints about guides or retreats.
For people using with friends or a partner. This card describes sessions with one facilitator and one person, in groups, and with a couple. A friend or partner sitting for someone has its own entry, not yet written. Almost all of this work involved people with a diagnosis. In a documented search, no source read in full compared formats among healthy adults. The authors of a 2023 pilot in people with cancer and depression warn of heightened suggestibility in groups. A controlled study of couples sessions with a substance was not located. This card does not say which format suits anyone.

The short answer

How do the formats differ, and what is known about couples?

Published sources describe sessions with one facilitator and one person, in groups, and with a couple. Almost all of this work involved people with a diagnosis. In a documented search, no source read in full compared formats among healthy adults. This entry does not say which format suits anyone.

What was found?

Reported findings, not recommendations.

  • Groups, people with a diagnosis. In a 2020 US pilot of 18 older long-term AIDS survivor men with demoralization, psilocybin groups of six met with two therapists before and after, while each man’s session with the substance was individual. In a 2023 US pilot of 12 people with cancer and depression, cohorts of four shared one session, with a therapist per participant and a lead. Neither had a comparison arm. The 2023 authors say group and psilocybin effects are hard to separate, and warn of heightened suggestibility in groups. Sources 1, 2, level 1
  • Earlier work and a 2026 review, people with a diagnosis. A systematic review of 12 studies from 1959 to 1995, mostly LSD, in people with alcohol dependence or “neurotic” diagnoses reports group sizes from 2 to 23 in most. Its authors say the results do not permit comment on efficacy, and the one controlled group-versus-individual comparison also differed in amount. Source 3, level 1 A 2026 systematic review of 30 papers on group psychedelic therapy, limited by design to people with a psychiatric diagnosis, says current evidence is insufficient to determine the group component’s contribution relative to individual therapy. Source 10, level 1
  • Healthy adults. In a 2019 placebo-controlled study, 39 experienced meditators found healthy on screening took part in a silent five-day retreat held in two groups, of 16 and 23. The authors suggest the presence of others may have helped, but the retreat limited exchange and no other format was tested. Source 4, level 1
  • Couples, people with PTSD. In a 2020 uncontrolled study, six couples in which one partner had PTSD had couples therapy with two sessions in which both partners received MDMA. Source 5, level 1 A 2021 report on the same six couples, one partner of each with PTSD, covers their relationship outcomes, and its authors write that efficacy conclusions cannot be drawn. Source 6, level 1 In a 2026 uncontrolled pilot, eight veterans with PTSD and their partners took part. Only the veteran received MDMA, and the partner joined for the last hour or two. One partner reported a reliable decrease in relationship satisfaction, and gains partly receded at follow-up. Source 7, level 1 All three are small and uncontrolled.
  • Couples outside clinics. A 2019 interview and diary study of 14 people who had taken MDMA with a partner five or more times describes preparing the space and keeping others out. It measured no outcomes and reported no psychiatric diagnosis. Source 8, level 1
  • Oregon’s rules. As of 7 November 2026, rule 333-333-5230 limits a group administration session to 25 clients, or the service center’s maximum occupancy if that is smaller. The minimum facilitator-to-client ratio depends on the amount of psilocybin product clients will individually consume, the largest amount setting it: 1 to 25 for clients consuming less than 5 mg of psilocybin analyte, down to 1 to 2 for clients consuming 35 mg and up to 50 mg. Source 9, level 1 State rule only. Federal law still applies.
  • Colorado's rules. As of 8 November 2026, group administration sessions are allowed at the facilitator's discretion, and each participant gives individual consent and has at least one individual preparation session. No more than 4 participants may be present per facilitator, or 8 if every participant's amount is no more than 2 mg of total psilocin, and no more than 64 in one session. Sessions outside a healing center may include individual participants only. Source 11, level 1 State rule only. Federal law still applies.

What is not known?

Searches on 7 November 2026 covered PubMed (11 strings), ClinicalTrials.gov (2) and Europe PMC preprints (1), several scanning only the first 25 to 30 titles. “Not located” means no source read in full showed it.

  • Whether format changes outcomes or difficulty among healthy adults, how group size matters, or any study that changed the format alone with amount, substance and population held the same. Not located.
  • A controlled study of couples sessions with a substance. Not located.
  • Group size at traditional ceremonies. It was not found in the sources read.
  • Two further papers, on naturalistic group settings and on couples, could not be opened in full and carry no claim.

What this card does not say

Send a correction

If this card reports something wrongly, tell us. Write to main@metanoia-ca.org and keep the card name in the subject line. Accounts of what happened in a session belong in the field reports channel, not in email. Please leave out names and anything that identifies a person or a place. We read every message.

Where does this come from?

Grade key: 1 = peer-reviewed publication or official rule text. A grade names the type of source and says nothing about its quality. “Read in full” means Metanoia read every sentence of the part cited on the date given, and any part not read is named.

Review due by 8 January 2027, before Oregon’s planned rule changes of 15 January 2027. Law and research change.

  1. Anderson BT, Danforth A, Daroff R, Stauffer C, Ekman E, Agin-Liebes G, Trope A, Boden MT, Dilley J, Mitchell J, Woolley J. Psilocybin-assisted group therapy for demoralized older long-term AIDS survivor men: an open-label safety and feasibility pilot study. EClinicalMedicine 2020. DOI 10.1016/j.eclinm.2020.100538. PMID 33150319. Grade 1. Open-label pilot, diagnosed population. Read in full 7 November 2026 (PMC7599297). Supplement and references not read.
  2. Lewis BR, Garland EL, Byrne K, Hendrick J, Beck A, Thielking P and others. HOPE: a pilot study of psilocybin enhanced group psychotherapy in patients with cancer. J Pain Symptom Manage 2023. DOI 10.1016/j.jpainsymman.2023.06.006. PMID 37302533. Grade 1. Open-label pilot, diagnosed population. Read in full 7 November 2026 from the journal site. Figures and part of the reference list not read.
  3. Trope A, Anderson BT, Hooker AR, Glick G, Stauffer C, Woolley JD. Psychedelic-assisted group therapy: a systematic review. J Psychoactive Drugs 2019. DOI 10.1080/02791072.2019.1593559. PMID 30950777. Grade 1. Systematic review of historical studies, diagnosed populations. Read in full 7 November 2026 (author manuscript, PMC6650145). Figure and references not read.
  4. Smigielski L, Kometer M, Scheidegger M, Krähenmann R, Huber T, Vollenweider FX. Characterization and prediction of acute and sustained response to psychedelic psilocybin in a mindfulness group retreat. Sci Rep 2019. DOI 10.1038/s41598-019-50612-3. PMID 31649304. Grade 1. Placebo-controlled study, healthy experienced meditators. Read in full 7 November 2026 (PMC6813317). Supplement not read.
  5. Monson CM, Wagner AC, Mithoefer AT, Liebman RE, Feduccia AA, Jerome L, Yazar-Klosinski B, Emerson A, Doblin R, Mithoefer MC. MDMA-facilitated cognitive-behavioural conjoint therapy for posttraumatic stress disorder: an uncontrolled trial. Eur J Psychotraumatol 2020. DOI 10.1080/20008198.2020.1840123. PMID 33408811. Grade 1. Uncontrolled trial, diagnosed population, some authors paid by the funder of the substance work. Read in full 7 November 2026 (PMC7748057). Supplement not read.
  6. Wagner AC, Liebman RE, Mithoefer AT, Mithoefer MC, Monson CM. Relational and growth outcomes following couples therapy with MDMA for PTSD. Front Psychiatry 2021. DOI 10.3389/fpsyt.2021.702838. PMID 34262496. Grade 1. Secondary outcomes of the same six couples. Read in full 7 November 2026 (PMC8273271).
  7. Morland LA, Khalifian CE, Perivoliotis D, Chargin B, Alam A, Wachsman TR, Ramanathan D, Bismark AW, Stauffer C, Wagner AC, Angkaw AC, Knopp KC. Healing together: results from a pilot trial of MDMA-enhanced cognitive-behavioral conjoint therapy for PTSD. J Trauma Stress 2026 (early view). DOI 10.1002/jts.70126. PMID 42693902. Grade 1. Open-label pilot, diagnosed population. Read in full 7 November 2026 from the journal site. Supplementary tables, figure captions and references not read.
  8. Anderson K, Reavey P, Boden ZVR. ‘Never drop without your significant other, cause that way lies ruin’: the boundary work of couples who use MDMA together. Int J Drug Policy 2019. DOI 10.1016/j.drugpo.2019.05.004. PMID 31170684. Grade 1. Qualitative study, self-selected sample. Read in full 7 November 2026 as the accepted manuscript. References not read.
  9. Oregon Administrative Rules 333-333-5230 (group administration sessions), 333-333-5200 and 333-333-5020. Oregon Secretary of State. OAR 333-333-5230, 5200, 5020. Grade 1. Rule text. Read in full 7 November 2026 on the official site, where the last amendment shown took effect on 1 January 2026. Only the two ends of the ratio table are quoted.
  10. Tsang VWL, Bhatia F, Ferrey A, Hartmann-Boyce J. Group psychedelic-assisted therapy for mental health conditions: a mixed-methods systematic review. Front Public Health 2026. DOI 10.3389/fpubh.2026.1788352. PMID 42903078. Grade 1. Systematic review limited to people with a psychiatric diagnosis. Read in full 7 November 2026 (PMC13680196, full-text XML). Reference list, figure and supplement not read.
  11. Colorado Code of Regulations, 4 CCR 755-1, Natural Medicine Licensure Rules, rules 6.16, 6.17 and 6.18, official PDF of the version effective 5 December 2025. Grade 1. Official rule text. Section 6 read in full on 8 November 2026. Other sections were not used.