Evidence
Peer-reviewed work on psychedelic medicine, with the caveats intact: sample sizes, blinding problems and null results included.
50 studies
Lewis-Healey E, Pallavicini C, Cavanna F, D'Amelio T, De La Fuente LA, Copa D, et al. · Journal of Cognitive Neuroscience
EEG study of 19 people on 20 mg and 40 mg DMT: alpha power tracked experience best; a popular complexity measure tracked it worst.
Roberts C, Seynaeve M, Ermakova AO, Dunbar F, Wells H, Puri A, et al. · Journal of Psychopharmacology
Open-label phase 2a trial: one intranasal 5-MeO-DMT dose in 12 people with treatment-resistant depression, with quick, lasting score drops and mostly mild side effects.
Agrawal M, Roddy K, Jenkins B, Leeks C, Emanuel E · Cancer
Two years after one psilocybin dose with support, about half of 28 cancer patients with major depression still had reduced depression.
Davis AK, DellaCrosse MA, Sepeda ND, Levin AW, Cosimano M, Shaub H, et al. · Journal of Psychedelic Studies
Five years after a psilocybin trial for major depression, 67% of followed-up participants were in remission; small sample, no control group.
Jevotovsky DS, Chopra H, Pak DJ, Durbhakula S, Shustorovich A, Juneja T, et al. · Regional Anesthesia & Pain Medicine
Systematic review of 28 studies on psilocybin for chronic pain found possible benefit but mostly low or very low quality evidence.
ClinicalTrials.gov
Registered placebo-controlled trial of weekly sublingual 5-MeO-DMT in 20 people with cognitive impairment; completed 2025, no results published.
Back AL, Freeman-Young TK, Morgan L, Sethi T, Baker KK, Myers S, et al. · JAMA Network Open
Randomised trial in 30 frontline clinicians: one psilocybin dose cut depression far more than niacin at 28 days; burnout gain not significant.
Cherian KN, Keynan JN, Anker L, Faerman A, Brown RE, Shamma A, et al. · Nature Medicine
Open-label study of 30 veterans with brain injury: magnesium-ibogaine was followed by large drops in disability, PTSD, depression and anxiety at 1 month.
Kwaśny A, Wilkowska A, Cubała WJ · Frontiers in Psychiatry
Review of the only 3 clinical trials of 5-MeO-DMT (78 people) found no serious adverse events, but the evidence is very limited.
Timmermann C, Zeifman RJ, Erritzoe D, Nutt DJ, Carhart-Harris RL · Scientific Reports
In two small groups of healthy volunteers, intravenous DMT was followed by lower depression scores one to two weeks later.
Ragnhildstveit A, Khan R, Seli P, Bass LC, August RJ, Kaiyo M, et al. · Frontiers in Psychiatry
Case report: one woman with refractory PTSD improved after a single inhalation of toad-derived 5-MeO-DMT, with gains lasting 12 months.
Timmermann C, Roseman L, Haridas S, Rosas FE, Luan L, Kettner H, et al. · Proceedings of the National Academy of Sciences
EEG-fMRI in 20 healthy volunteers found intravenous DMT sharply increased whole-brain connectivity, tracking the intensity of the experience.
Daws RE, Timmermann C, Giribaldi B, Sexton JD, Wall MB, Erritzoe D, et al. · Nature Medicine
Brain scans from two depression trials: improvement after psilocybin went with more integrated brain networks, a change not seen with escitalopram.
Goodwin GM, Aaronson ST, Alvarez O, Arden PC, Baker A, Bennett JC, et al. · New England Journal of Medicine
Phase 2 trial in 233 adults: one 25 mg psilocybin dose cut depression scores more than 1 mg at 3 weeks; side effects were common.
Carhart-Harris R, Giribaldi B, Watts R, Baker-Jones M, Murphy-Beiner A, Murphy R, et al. · New England Journal of Medicine
Psilocybin vs escitalopram in 59 people with depression: no significant difference on the main measure at 6 weeks; secondary measures leaned towards psilocybin.
Davis AK, Barrett FS, May DG, Cosimano MP, Sepeda ND, Johnson MW, et al. · JAMA Psychiatry
Waitlist-controlled trial in 24 adults with major depression: two psilocybin sessions with therapy brought large, rapid symptom drops over 4 weeks.
Mitchell JM, Bogenschutz M, Lilienstein A, Harrison C, Kleiman S, Parker-Guilbert K, et al. · Nature Medicine
Phase 3 trial in 90 people with severe PTSD: MDMA plus therapy reduced symptoms more than placebo plus therapy at 2 months.
Barrett FS, Doss MK, Sepeda ND, Pekar JJ, Griffiths RR · Scientific Reports
Pilot fMRI study of 12 healthy volunteers found mood and brain changes lasting up to a month after one high psilocybin dose.
Bershad AK, Schepers ST, Bremmer MP, Lee R, de Wit H · Biological Psychiatry
Double-blind lab study of 20 healthy adults: single LSD microdoses had noticeable effects but did not improve mood or cognition.
Johnson MW, Hendricks PS, Barrett FS, Griffiths RR · Pharmacology & Therapeutics
Broad review of classic psychedelics covering population studies, early clinical trials, mystical experience and brain imaging, as of 2019.
Palhano-Fontes F, Barreto D, Onias H, Andrade KC, Novaes MM, Pessoa JA, et al. · Psychological Medicine
Placebo-controlled trial in 29 people with treatment-resistant depression: one ayahuasca dose cut depression scores within a week.
Polito V, Stevenson RJ · PLOS ONE
Six weeks of tracking 98 microdosers found modest self-reported gains on dosing days, and expectations that far outran reported effects.
Uthaug MV, Lancelotta R, van Oorsouw K, Kuypers KPC, Mason N, Rak J, et al. · Psychopharmacology
Observational study of 42 people: one inhalation of toad-derived 5-MeO-DMT was followed by better life satisfaction and lower depression at 4 weeks.
Brown TK, Alper K · American Journal of Drug and Alcohol Abuse
Observational study of 30 people with opioid dependence: after ibogaine detox, half reported no opioid use at 1 month; gains partly faded.
Danforth AL, Grob CS, Struble C, Feduccia AA, Walker N, Jerome L, et al. · Psychopharmacology
Randomised pilot in 12 autistic adults found MDMA-assisted therapy reduced social anxiety more than placebo, with gains holding at six months.
Davis AK, Barsuglia JP, Lancelotta R, Grant RM, Renn E · Journal of Psychopharmacology
Survey of 515 people who used 5-MeO-DMT found mostly rare, spiritually motivated use and self-reported mental health improvements.
Griffiths RR, Johnson MW, Richards WA, Richards BD, Jesse R, MacLean KA, et al. · Journal of Psychopharmacology
Randomised trial in 75 healthy meditators: high-dose psilocybin led to lasting gains in gratitude, closeness and life meaning at 6 months.
Johnson MW, Griffiths RR, Hendricks PS, Henningfield JE · Neuropharmacology
Review applying the US Controlled Substances Act's 8 factors to psilocybin: low abuse potential, manageable risks under medical supervision.
Noller GE, Frampton CM, Yazar-Klosinski B · The American Journal of Drug and Alcohol Abuse
Small New Zealand follow-up of 14 people found less opioid use and depression a year after one ibogaine treatment; one participant died.
Johnson MW, Garcia-Romeu A, Griffiths RR · The American Journal of Drug and Alcohol Abuse
Follow-up of 15 smokers given psilocybin with CBT: 67% were confirmed smoke-free at 12 months, 60% at an average 30 months.
Carhart-Harris RL, Bolstridge M, Rucker J, Day CM, Erritzoe D, Kaelen M, et al. · The Lancet Psychiatry
Open-label study of 12 patients with treatment-resistant depression: two psilocybin doses were tolerated and depression scores fell through 3 months.
Dos Santos RG, Osório FL, Crippa JA, Hallak JE · Revista Brasileira de Psiquiatria
Systematic review of 21 animal and human studies found early, mostly uncontrolled evidence that ayahuasca may ease anxiety and depression.
Frecska E, Bokor P, Winkelman M · Frontiers in Pharmacology
Narrative review of ayahuasca's therapeutic potential, proposing a sigma-1 receptor anti-inflammatory mechanism alongside its serotonergic effects.
Griffiths RR, Johnson MW, Carducci MA, Umbricht A, Richards WA, Richards BD, et al. · Journal of Psychopharmacology
Crossover trial in 51 cancer patients: high-dose psilocybin cut depression and anxiety, with about 80% still improved at 6 months.
Ross S, Bossis A, Guss J, Agin-Liebes G, Malone T, Cohen B, et al. · Journal of Psychopharmacology
Crossover trial in 29 cancer patients: one psilocybin dose with psychotherapy quickly reduced anxiety and depression, with benefits seen at 6.5 months.
Sanches RF, de Lima Osório F, Dos Santos RG, Macedo LR, Maia-de-Oliveira JP, Wichert-Ana L, et al. · Journal of Clinical Psychopharmacology
Open-label study of 17 inpatients with recurrent depression found one ayahuasca dose lowered depression scores for 21 days and changed brain blood flow.
Szabo A, Kovacs A, Riba J, Djurovic S, Rajnavolgyi E, Frecska E · Frontiers in Neuroscience
Cell-culture study found DMT helped human neurons and immune cells survive severe oxygen deprivation through the sigma-1 receptor.
Tagliazucchi E, Roseman L, Kaelen M, Orban C, Muthukumaraswamy SD, Murphy K, et al. · Current Biology
fMRI study in healthy volunteers: LSD increased global brain connectivity, and the increase tracked self-reported ego dissolution.
Bogenschutz MP, Forcehimes AA, Pommy JA, Wilcox CE, Barbosa PC, Strassman RJ · Journal of Psychopharmacology
Pilot study of 10 people with alcohol dependence: drinking fell after psilocybin plus therapy, with gains largely holding to 36 weeks.
Gasser P, Kirchner K, Passie T · Journal of Psychopharmacology
Twelve-month follow-up of 10 seriously ill patients after LSD-assisted psychotherapy: anxiety reductions held and no lasting harms were reported.
Brown TK · Current Drug Abuse Reviews
Review of ibogaine for addiction: animal research supports reduced withdrawal and craving, but safety concerns and scarce human data remain.
Krebs TS, Johansen PØ · PLoS ONE
US survey of 130,152 adults: lifetime psychedelic use was not linked to higher rates of mental health problems.
Carhart-Harris RL, Erritzoe D, Williams T, Stone JM, Reed LJ, Colasanti A, et al. · Proceedings of the National Academy of Sciences of the United States of America
fMRI study in 30 healthy volunteers: intravenous psilocybin reduced activity and connectivity in key brain hubs, tracking the intensity of effects.
Cunningham CW, Rothman RB, Prisinzano TE · Pharmacological Reviews
Review of how salvinorin A, from Salvia divinorum, acts on kappa-opioid receptors and where it might have medical uses.
Mithoefer MC, Wagner MT, Mithoefer AT, Jerome L, Doblin R · Journal of Psychopharmacology
First randomised pilot of MDMA-assisted psychotherapy: 10 of 12 PTSD patients responded vs 2 of 8 on placebo, without serious drug-related harms.
Griffiths RR, Richards WA, McCann U, Jesse R · Psychopharmacology
Double-blind study of 36 volunteers: high-dose psilocybin occasioned mystical-type experiences rated as personally meaningful two months later.
Zarate CA, Singh JB, Carlson PJ, Brutsche NE, Ameli R, Luckenbaugh DA, et al. · Archives of General Psychiatry
Crossover trial in 18 people with treatment-resistant depression: one ketamine infusion lifted mood within hours, but effects faded for most within a week.
Halpern JH, Sherwood AR, Hudson JI, Yurgelun-Todd D, Pope HG · Biological Psychiatry
Navajo Native American Church members who regularly use peyote showed no mental health or cognitive deficits compared with non-users.
Berman RM, Cappiello A, Anand A, Oren DA, Heninger GR, Charney DS, et al. · Biological Psychiatry
First placebo-controlled trial of ketamine for depression: in 7 patients, one infusion cut depression scores within 72 hours.
Glick SD, Kuehne ME, Raucci J, Wilson TE, Larson D, Keller RW, et al. · Brain Research
Rat study found ibogaine and related alkaloids reduced morphine and cocaine self-administration, sometimes for several days after one dose.
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