OCD and Eating Disorders Research

How to read this page

Obsessive-compulsive disorder (OCD) and eating disorders are serious conditions with established care from clinicians. This page summarizes early research on psilocybin. It does not suggest using psilocybin for either condition. Evidence labels used: approved medicine, promising but limited, insufficient evidence, and Proper evidence not found where we looked and found nothing usable. For both conditions the evidence is at the pilot level: very small groups, short follow-up, and researchers who often knew who got what. If you are in crisis in the US, call or text 988, the Suicide & Crisis Lifeline.

Obsessive-compulsive disorder (OCD)

Usual treatments are serotonin reuptake inhibitor medicines, add-on antipsychotics and cognitive-behavioral therapy, yet up to 60% of people with OCD do not respond to them, according to the authors of a recent trial plan. [1] That gap is why researchers have tested psilocybin.

First small study (2006). Nine adults with OCD and no other current major psychiatric disorder took part in up to four single-dose sessions in a controlled clinic, with a very low dose inserted at random in a modified double-blind design. [2] Symptoms fell in all nine during at least one session, but the effect of dose was not statistically significant, and one participant had transient high blood pressure. [2] With only nine people and no placebo group in the usual sense, the study could show feasibility and short-term safety, not that psilocybin treats OCD.

Randomized pilot trial (2026). Fifteen participants were assigned to high-dose psilocybin, low-dose psilocybin or an active placebo, the sedative lorazepam, with five per group in a double-blind first phase. [3] The second phase gave four more high-dose sessions on a single-blind basis. [3] Psilocybin, but not placebo, reduced symptom scores on the Yale-Brown scale. [3] After at least four high doses, 73.3% were responders and 40% were in remission; effects diminished but remained substantial at 6 months. [3] No serious adverse events or psychotic symptoms were reported. [3]

Why caution? The headline response figure comes after the second phase, which was single-blind and gave every participant high-dose psilocybin, so it no longer compares psilocybin with placebo. [3] The authors describe the cumulative-dose link as post hoc, and say larger trials are needed. [3] Label: promising but limited.

Protocols are not results. A 2025 paper describes the plan for an open-label pilot in treatment-resistant OCD. [1] It tells us what researchers intend to measure, not what happened. See finding and understanding registered clinical trials.

Eating disorders

Anorexia nervosa (AN) is a dangerous illness, and the authors of the main psilocybin study note that no medications are approved by the US Food and Drug Administration for it. [4] Fluoxetine remains the only drug approved for bulimia nervosa, and none is approved for other eating disorders. [5]

Open-label feasibility study (2023). Ten adult women with AN or partial remission received a single dose of synthetic psilocybin with psychological support. [4] The main aim was safety, tolerability and feasibility, measured through side effects, ECG, lab tests, vital signs and suicidality. [4] No clinically significant changes were seen on ECG, vital signs or suicidality; two participants had asymptomatic low blood sugar that resolved within 24 hours, and all adverse events were mild and short-lived. [4] The study was funded by Compass Pathways, and the lead author consults for that company. [4]

This was a first look at safety and acceptability in 10 people. It did not test whether psilocybin improves weight, eating behavior or relapse, and it had no control group. Label: insufficient evidence of benefit.

Systematic review (2025). Searching to mid-2024, reviewers found only two eligible studies, the 10-person study and one case report, plus six registered clinical trials not yet reported. [5] They concluded that psilocybin might be safe and well tolerated in AN and that larger samples are needed. [5]

Proper evidence not found

We looked for randomized trials of psilocybin in OCD with long follow-up, and for any controlled trial of psilocybin in bulimia nervosa or binge-eating disorder, in the reviews above and a PubMed search on 2026-10-22. [5] None was found. Evidence for LSD or other psychedelics in these conditions was also not found in what we read.

Safety and who should talk to a clinician first

People with eating disorders can have heart, electrolyte and blood sugar problems, and the 2023 study tracked ECG and labs closely. [4] Findings from monitored research clinics do not transfer to home use. Mental health conditions and medicine interactions matter; see adverse effects and contraindications and psilocybin. Do not stop or change psychiatric medicines without your prescriber.