Updated · July 2026 · 39 studies
Research Library
The studies that actually moved the field — landmark trials, foundational safety work, and the honest null results — each summarized in plain language and linked to the original paper. Curated for signal, not volume.
Clinical trials happen under careful screening, calibrated doses, and professional support — conditions that don't transfer automatically to other contexts. Positive findings are evidence of what's possible under those conditions, not a promise. We include null and cautionary results deliberately.
Magnesium–ibogaine therapy in veterans with traumatic brain injuries
Stanford observational study of special-operations veterans treated in Mexico: one magnesium-ibogaine session was followed by large improvements in PTSD, depression, anxiety, and disability, with no cardiac events under monitoring.
Single-dose psilocybin treatment for major depressive disorder
A rigorous randomized trial with an active placebo (niacin): a single 25 mg dose with psychological support produced a large, sustained reduction in depression over six weeks.
MDMA-assisted therapy for moderate to severe PTSD: a randomized, placebo-controlled phase 3 trial
The confirmatory Phase 3 trial replicated the first in a more diverse sample. Despite both trials meeting endpoints, the FDA declined approval in 2024 and requested an additional study.
Lysergic acid diethylamide-assisted therapy in patients with anxiety with and without a life-threatening illness
Modern randomized trial of LSD for anxiety disorders: two 200 µg sessions produced rapid, robust reductions in anxiety and depression sustained at 16 weeks.
Human brain effects of DMT assessed via EEG-fMRI
Simultaneous EEG-fMRI during the DMT peak: profound disintegration of higher-level cortical networks with increased global connectivity — the most detailed picture yet of a psychedelic’s acute brain action.
Single-dose psilocybin for a treatment-resistant episode of major depression
The largest psilocybin trial to date (233 participants, 22 sites): 25 mg significantly reduced treatment-resistant depression versus 1 mg control at three weeks, though effects waned in a subset and adverse events were not trivial.
Percentage of heavy drinking days following psilocybin-assisted psychotherapy vs placebo
In the first modern RCT for alcohol use disorder (93 participants), two psilocybin sessions within psychotherapy roughly halved heavy drinking days over 32 weeks compared with active placebo.
Microdosing with psilocybin mushrooms: a double-blind placebo-controlled study
Double-blind study in a natural setting: acute measures showed subtle perceptible effects, but cognitive, creative, and wellbeing outcomes did not separate from placebo.
The relationship between psychedelic use, mystical experiences, and pro-environmental behaviors
Among 240 psychedelic-experienced participants, mystical-type experiences specifically — not use alone — predicted pro-environmental behavior, suggesting the quality of the experience drives the ecological shift.
Trial of psilocybin versus escitalopram for depression
Head-to-head against a standard SSRI over six weeks, psilocybin therapy performed at least as well on the primary measure and better on most secondary measures — though the trial was not powered to establish superiority.
Effects of psilocybin-assisted therapy on major depressive disorder
Randomized waiting-list trial in major depression: two psilocybin sessions with supportive therapy produced large, rapid antidepressant effects, with over half of participants in remission at four weeks.
MDMA-assisted therapy for severe PTSD: a randomized, double-blind, placebo-controlled phase 3 study
The first Phase 3 trial: 67% of participants receiving MDMA-assisted therapy no longer met PTSD diagnostic criteria after three sessions, versus 32% with placebo plus identical therapy.
A phase 1, dose-ranging study to assess safety and psychoactive effects of a vaporized 5-methoxy-N,N-dimethyltryptamine formulation (GH001)
First formal Phase 1 trial of vaporized 5-MeO-DMT: single doses were tolerated in healthy volunteers with rapid, short-lived, dose-dependent peak experiences.
Self-blinding citizen science to explore psychedelic microdosing
The largest placebo-controlled microdosing study (191 participants self-blinding their own doses): microdosers improved on wellbeing measures — but so did placebo, with no significant difference between them.
Rapid antidepressant effects of the psychedelic ayahuasca in treatment-resistant depression: a randomized placebo-controlled trial
The first RCT of ayahuasca: a single session produced significant antidepressant effects versus placebo within a week in treatment-resistant patients.
The epidemiology of 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) use: benefits, consequences, patterns of use
Survey of 5-MeO-DMT users: most reported improvements in depression and anxiety after use, alongside meaningful rates of challenging effects — motivating controlled study.
Efficacy and safety of flexibly dosed esketamine nasal spray combined with a newly initiated oral antidepressant in treatment-resistant depression
A pivotal trial behind Spravato — the intranasal esketamine formulation that became the first psychedelic-adjacent medicine to win FDA approval (2019).
A systematic study of microdosing psychedelics
Six-week daily-diary study: small improvements in depression and stress and reduced mind-wandering, but effects were selective and did not match the sweeping claims of microdosing folklore.
REBUS and the anarchic brain: toward a unified model of the brain action of psychedelics
The most influential theoretical model of how psychedelics work: relaxation of high-level beliefs (priors) allows bottom-up information to revise entrenched patterns of mind.
From egoism to ecoism: psychedelics increase nature relatedness in a state-mediated and context-dependent manner
Prospective study tracking people before and after planned psychedelic experiences: nature relatedness rose after use and stayed elevated at two years, mediated by ego dissolution and amplified by natural settings.
Ibogaine treatment outcomes for opioid dependence from a twelve-month follow-up observational study
Observational study of legal ibogaine treatment in New Zealand: a single treatment reduced opioid withdrawal and craving, with a subset achieving sustained abstinence at 12 months.
Treatment of opioid use disorder with ibogaine: detoxification and drug use outcomes
Mexico clinic outcomes: ibogaine substantially reduced opioid withdrawal symptoms and use at follow-up — alongside a cardiac risk profile that makes medical screening and monitoring non-negotiable.
Psychedelics promote structural and functional neural plasticity
Preclinical foundation for the neuroplasticity hypothesis: psychedelics increased dendritic growth and synapse formation in cortical neurons, comparable to ketamine.
Increased nature relatedness and decreased authoritarian political views after psilocybin for treatment-resistant depression
In a clinical sample, nature relatedness increased significantly after psilocybin therapy and remained elevated at 7–12 months — evidence that the connection shift is a lasting effect, not an acute mood artifact.
Lifetime experience with (classic) psychedelics predicts pro-environmental behavior through an increase in nature relatedness
In a large survey, lifetime psychedelic use predicted self-reported pro-environmental behavior — an effect statistically explained by feeling more connected to nature. The study that opened the psychedelics–ecology research line.
Psilocybin produces substantial and sustained decreases in depression and anxiety in patients with life-threatening cancer
In a randomized double-blind crossover trial, a single high dose produced large, sustained reductions in depression and anxiety in cancer patients, with ~80% showing clinically significant response at six months.
Rapid and sustained symptom reduction following psilocybin treatment for anxiety and depression in patients with life-threatening cancer
The parallel NYU trial: a single psilocybin session with psychotherapy produced immediate and enduring reductions in cancer-related existential distress, mediated by mystical-type experience.
Neural correlates of the LSD experience revealed by multimodal neuroimaging
The first modern neuroimaging study of LSD: expanded visual cortex connectivity tracked hallucinations, while decreased default mode network integrity tracked ego dissolution.
Survey study of challenging experiences after ingesting psilocybin mushrooms: acute and enduring positive and negative consequences
Among ~2,000 people reporting their most difficult psilocybin experience: 39% rated it among the most challenging of their lives, yet 84% endorsed having benefited — difficulty and value are not opposites.
Classic psychedelic use is associated with reduced psychological distress and suicidality in the United States adult population
Population-level analysis of ~190,000 US adults: lifetime classic psychedelic use was associated with reduced psychological distress and suicidality — correlational, but contrary to the assumption of population harm.
Pilot study of the 5-HT2AR agonist psilocybin in the treatment of tobacco addiction
Small open-label pilot in long-term smokers: 80% biologically confirmed abstinence at six months — far above typical cessation outcomes — motivating the larger randomized trials that followed.
Safety and efficacy of LSD-assisted psychotherapy for anxiety associated with life-threatening diseases
The first controlled LSD trial in over 40 years: LSD-assisted psychotherapy reduced anxiety in patients facing terminal illness, with benefits sustained at 12-month follow-up.
The safety and efficacy of ±3,4-methylenedioxymethamphetamine-assisted psychotherapy in subjects with chronic, treatment-resistant PTSD
The first randomized controlled trial of MDMA-assisted therapy: 83% clinical response in treatment-resistant PTSD versus 25% with placebo, launching the two-decade path toward Phase 3.
Drug harms in the UK: a multicriteria decision analysis
The famous harm-ranking analysis: across sixteen harm criteria, psilocybin mushrooms and LSD ranked among the least harmful drugs assessed — while alcohol ranked most harmful overall.
Human hallucinogen research: guidelines for safety
The safety framework underlying every modern trial: screening criteria, preparation, session conduct, and follow-up. Essential reading for understanding what "supported conditions" actually means.
Psilocybin can occasion mystical-type experiences having substantial and sustained personal meaning and spiritual significance
The landmark study that reopened modern psychedelic research: under supported conditions, a single high dose occasioned experiences participants ranked among the most meaningful of their lives, with benefits persisting at follow-up.
A randomized trial of an N-methyl-D-aspartate antagonist in treatment-resistant major depression
NIH replication in treatment-resistant depression: robust antidepressant effects within two hours of a single infusion, sustained for about a week — establishing ketamine’s clinical significance.
Antidepressant effects of ketamine in depressed patients
The serendipitous origin of rapid-acting antidepressants: a single sub-anesthetic ketamine infusion reduced depression within hours — an effect no conventional antidepressant produces.
Dose-response study of N,N-dimethyltryptamine in humans
The study that restarted US psychedelic research after a 20-year freeze: systematic characterization of intravenous DMT’s dose-dependent effects in healthy volunteers.