Screening and Eligibility in Clinical Research
What psychedelic trials and licensed programs screen for or exclude, and why. A description of published criteria, not a way to check yourself.
Content last updated . This page has not been medically reviewed.
Read this first
Screening is done by trained clinicians who can review a full history. This page describes what published trials and licensed programs have used. It is not a checklist, it cannot tell you whether any substance is safe for you, and it is not advice to start, stop or change any medicine. Talk with your own prescriber about medicines.Evidence label used here: where a trial excluded a group, safety and benefit in that group is insufficient evidence.
Why trials screen
Researchers' safety guidelines name the most likely risk as overwhelming distress during the drug's effects, which could lead to dangerous behavior, and less commonly prolonged psychosis. The safeguards they list include excluding people with a personal or family history of psychotic disorders or other severe psychiatric disorders. [1] The reasons are about risk and about clean results. The FDA also notes that enrolling people with prior psychedelic exposure can create expectation bias. [2]What published trials excluded
| Trial | Excluded or not eligible (as reported) |
|---|---|
| Psilocybin for major depression, 27 adults | People using antidepressant medications; histories of psychotic disorder, serious suicide attempt, or hospitalization [3] |
| MDMA for PTSD, phase 3, 104 adults | Authors list the exclusion of participants with high suicide risk, comorbid personality disorders and underlying cardiovascular disease as a limitation; also excluded were substance use disorders other than cannabis or alcohol in the prior 12 months [4] |
These are two trials among many. Other trials set different criteria, and we did not read their full protocols. Because these groups were excluded, results may not apply to them. See how to read a psychedelic clinical trial.
What the FDA says
- Heart valves. For drugs that act on the 5-HT2B receptor, the FDA says people with preexisting valvulopathy or pulmonary hypertension should be excluded until cardiac risk is characterized. [2]
- Medicines. The FDA notes that SSRIs, SNRIs or MAOIs used for 3 weeks or more may reduce the subjective effects of psychedelic drugs, while tricyclic antidepressants or lithium may potentiate them, creating a potential psychiatric safety concern. [2] The guidance says more research is needed. It describes trial design, not advice for patients. See serotonergic medicines and interactions and toxicology.
- Not excluding too much. The FDA also advises trials not to unnecessarily exclude groups who would use the treatment after approval. [2]
Oregon's licensed program
Oregon Health Authority (read 2026-10-22) lists reasons a client may be found ineligible: ideation of harm to self or others, having taken lithium within 30 days, or a diagnosis of active psychosis at any time. [5] Answers on the client information form may also mean a client must have an authorized support person present. [5] Clients must be 21 or older, and licensed facilitators may decline services for any reason. [5] The rules differ in other states and countries; this page does not cover them. Laws change and this is not legal advice.Colorado requires approved facilitator training to include Screening (5 hours) and Introduction to Suicide Risk (5 hours). [6]
Common questions about "self-screening"
No validated self-screening tool appeared in the sources we read. Proper evidence not found for a questionnaire or checklist shown to identify who can safely take psychedelics outside supervised care. We checked the FDA guidance, the safety guidelines and the trials above. Risks that screening tries to address are covered in contraindications, psychosis vulnerability and cardiovascular risks.Related guides
Frequently asked questions
Why do trials exclude people with psychosis in the family?
Safety guidelines name prolonged psychosis as a less common but serious risk and recommend excluding people with a personal or family history of psychotic disorders. [1]
Can I check at home whether I would be eligible?
No source we read supports that. Eligibility is judged by clinicians with your full history.
Do trials exclude people taking antidepressants?
Some do. One depression trial required participants not to be using antidepressants. [3] Never stop a medicine because of what a trial did; speak to your prescriber.
Does the FDA screen out heart conditions?
Its guidance says people with preexisting valvulopathy or pulmonary hypertension should be excluded from relevant trials until the risk is characterized. [2]
Where can I get help in a crisis?
In the US, call or text 988, or call 911 in an emergency.
References
- Johnson M, Richards W, Griffiths R. Human hallucinogen research: guidelines for safety. Journal of Psychopharmacology, 2008. Read 2026-10-22.
- U.S. Food and Drug Administration. Psychedelic Drugs: Considerations for Clinical Investigations, Guidance for Industry (July 2026). Read 2026-10-22.
- Davis AK et al. Effects of Psilocybin-Assisted Therapy on Major Depressive Disorder: A Randomized Clinical Trial. JAMA Psychiatry, 2021. Read 2026-10-22.
- Mitchell JM et al. MDMA-assisted therapy for moderate to severe PTSD, full text. Nature Medicine, 2023. Read 2026-10-22.
- Oregon Health Authority. Access Psilocybin Services. Read 2026-10-22.
- Colorado Division of Professions and Occupations. Natural Medicine FAQs. Read 2026-10-22.