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Research & Culture6 min readBy Shroomshack · Published October 17, 2026

Psilocybin Research Beyond Depression: Addiction, OCD, Anorexia and Serious Illness

Psilocybin Research Beyond Depression: Addiction, OCD, Anorexia and Serious Illness

Depression gets most of the headlines, but it is far from the only mental health condition researchers are studying with psilocybin. Over the past two decades, trials have looked at alcohol and tobacco addiction, obsessive-compulsive disorder, anorexia and the distress that can come with a life-threatening illness. Some of these studies are promising, most are small, and nearly all are early. Here is an honest tour of what each one tested and found.

The usual reminder applies: every study below gave measured doses of pure psilocybin to carefully screened people, with trained therapists before, during and after. None of it is medical advice, and none of it means mushrooms at home treat any of these conditions.

Why researchers look beyond depression

Many mental health conditions share a common thread: getting stuck. Cravings that keep pulling someone back to a drink, intrusive thoughts and rituals in OCD, rigid beliefs about food and body shape in anorexia. One reason psilocybin interests researchers is the idea that it may briefly loosen rigid patterns of thought, which our post on what brain research suggests explains in more detail. If that idea holds up, it could matter for more than one diagnosis.

Alcohol use disorder

The largest placebo-controlled trial outside depression so far was published in JAMA Psychiatry in 2022. A team led by Michael Bogenschutz at NYU randomly assigned 95 adults with alcohol use disorder to two sessions of either psilocybin or diphenhydramine, an antihistamine used as an active placebo, alongside 12 weeks of psychotherapy for everyone. Neither the participants nor the therapists were told which they had received.

Over the 32 weeks of the double-blind period, the psilocybin group drank heavily on about 9.7 per cent of days, compared with about 23.6 per cent in the placebo group, and no serious adverse events were reported among those who received psilocybin. That is a meaningful difference in a well-designed study. It is also one trial, and more than nine in ten participants correctly guessed which treatment they had received, which can inflate results. Larger trials are needed to confirm it.

Smoking

At Johns Hopkins, Matthew Johnson and colleagues ran a small pilot in which 15 long-term smokers received two or three psilocybin sessions as part of a cognitive behavioural therapy program. Six months later, 12 of the 15 were confirmed as abstinent by breath and urine tests. A long-term follow-up found that 9 of the original 15 were still smoke-free at an average of about two and a half years after their first session.

Those are unusually high quit rates for smoking, which is why the study is widely cited. It is also an uncontrolled study of 15 people who knew what they were taking, so it is a starting point, not proof.

Obsessive-compulsive disorder

Psilocybin research in OCD goes back to a 2006 study at the University of Arizona, led by Francisco Moreno. Nine people with OCD received up to four sessions at different doses. Every participant had a marked drop in symptoms during at least one session, ranging from 23 to 100 per cent on a standard OCD scale, though the effect did not clearly depend on dose and was measured only over the following day.

Twenty years later, the same group published a randomized trial in the Journal of Psychopharmacology. Fifteen participants first received four weekly sessions of high-dose psilocybin, low-dose psilocybin or lorazepam, a sedative used as an active placebo, without knowing which, followed by four more high-dose sessions. Psilocybin, but not the placebo, reduced symptoms. After eight weeks, 73 per cent of participants had responded and 40 per cent were in remission, with no serious adverse events, and the benefit had faded but was still substantial at six months. With five people in each group at the start, the authors are clear that larger trials are needed.

Anorexia nervosa

Anorexia has one of the highest death rates of any mental health condition and few effective treatments, so a 2023 study in Nature Medicine drew attention. Researchers at the University of California San Diego gave 10 women with anorexia a single 25 mg dose of psilocybin with psychological support. The main aim was safety: there were no serious adverse events, and the most notable side effect was low blood sugar in two participants, which resolved within a day.

Three months later, four of the ten had eating disorder scores back within the normal range for the general population. Weight was a different story: on average it did not change significantly. A small study without a control group like this cannot show whether psilocybin helped, but it was enough to justify larger trials.

Distress in serious illness

Some of the most striking results come from people facing a life-threatening diagnosis. In 2016, Johns Hopkins and NYU published two randomized trials side by side in the Journal of Psychopharmacology, involving 51 and 29 people with cancer and significant depression or anxiety. Both found large, lasting reductions after a single high-dose session. Our research explainer covers them in detail.

What came next is what makes this area stand out. In 2020, the NYU team contacted the surviving participants again, an average of 3.2 and 4.5 years after their session. Fifteen agreed, and roughly 60 to 80 per cent still met the criteria for a clinically significant improvement in depression or anxiety. Most of them credited the therapy with positive changes in their lives. Because everyone in the original trial eventually received psilocybin, the follow-up cannot separate its effect from everything else that happened over those years.

Also in 2020, a team at the University of California San Francisco tested psilocybin with group therapy in 18 older gay men who were long-term survivors of AIDS, a group with high rates of demoralization, a mix of hopelessness and loss of purpose. Their demoralization scores dropped meaningfully by three months, and no serious adverse reactions were attributed to psilocybin. Again, the study was small and uncontrolled, but it was the first modern psilocybin trial to use a group format.

The pattern across all of these

  • Results are often encouraging, but most trials are small, and several had no control group.
  • People can usually tell whether they had a psychedelic, which makes placebo comparisons hard.
  • Psilocybin was always one part of a structured program with preparation, support and follow-up.
  • Participants were carefully screened and monitored, and people with a history of psychosis or bipolar disorder were generally excluded.

That is why researchers describe these as promising leads rather than established treatments. For some conditions, such as alcohol use disorder, the evidence is stronger; for others, such as anorexia, it is only beginning.

If you're struggling

Addiction, OCD, eating disorders and illness-related distress are all serious, and effective support exists for each. Talk to your doctor about your options, including clinical trials. In Canada, legal access to psilocybin for a medical need runs through Health Canada's Special Access Program or an authorized trial, as our Canada guide explains. If you are thinking about suicide or are in crisis, call or text 9-8-8 at any time, or call 911.

Sources

What the research says

Research on psilocybin is still young, and most trials give a measured dose with professional support. Results don't mean any product is safe or effective for you.

This guide is general information, not medical or legal advice. If you have health questions, talk to a health professional.