Psilocybin for Parkinson’s Disease: Promising Pilot Results

Parkinson's disease is best known for its effects on movement, such as tremor, stiffness, and slowness. For many people living with it, though, some of the hardest symptoms are ones others can't see. Depression and anxiety are among the most common non-motor symptoms of Parkinson's, and they can take a major toll on quality of life and daily functioning. Unfortunately, standard mood treatments often work less well for people with Parkinson's.

A pilot study from the University of California, San Francisco (UCSF), published in Neuropsychopharmacology in 2025, offers new hope. Researchers found that psilocybin-assisted therapy was well tolerated by people with Parkinson's disease and was linked to lasting improvements in depression and anxiety. Participants also showed encouraging gains in other Parkinson's symptoms, thinking skills, and overall wellbeing. It was the first study to examine psilocybin's effects in any neurodegenerative disease.

Why Do People With Parkinson's Need New Mood Treatments?

Depression and anxiety affect a large share of people with Parkinson's, and they are a leading predictor of how quickly daily functioning declines. Despite this, few clinical trials have explored new treatments for mood symptoms in Parkinson's.

Psilocybin has shown promise for depression and anxiety in other groups, including people with major depression and people facing life-threatening cancer. However, people with neurodegenerative conditions have typically been excluded from these trials because of safety questions. Researchers wanted to know whether psilocybin could affect blood pressure, movement, or the risk of hallucinations in people with Parkinson's. This study set out to answer those questions carefully.

How Was Psilocybin Therapy Studied in Parkinson's Disease?

The study included 12 adults, with an average age of 63, who had mild to moderate Parkinson's along with depression, anxiety, or both. Nine of them continued taking their regular Parkinson's medication, carbidopa-levodopa, throughout the study.

Each participant was paired with a licensed therapist, and the treatment was carefully structured:

• Preparation: Three meetings with their therapist before the first session to build trust and learn what to expect.
• A lower first dose: A 10 mg psilocybin session, which served as a safety check, followed by two more therapist meetings.
• A full treatment dose: A 25 mg session about two weeks later, followed by three meetings to help participants reflect on and make sense of their experiences.

Both sessions took place in a quiet room at UCSF, with the therapist present throughout and a physician on site. A movement disorder specialist was available by phone. Participants stayed overnight under supervision after each session and were checked by a physician the next morning before going home.

Is Psilocybin Safe for People With Parkinson's Disease?

The results were reassuring. There were no serious adverse events, and no participant needed medical treatment to manage psilocybin's effects. The most common side effects were anxiety, nausea, headache, and temporary rises in blood pressure and heart rate during sessions. All of these resolved on their own.

Importantly, psilocybin did not worsen Parkinson's symptoms or trigger hallucinations. In fact, the mild psychotic symptoms some participants had at the start decreased after treatment. Thinking skills did not decline, and thoughts of suicide decreased across the group. Participants taking levodopa tolerated psilocybin just as well as those who weren't.

As in other psilocybin research, a few people found the experience challenging. Two participants had especially difficult sessions, which is a reminder of why careful screening and skilled support matter.

Key Findings: How Psilocybin Affected Mood, Movement, and Thinking

The improvements reached further than researchers expected:

• Depression relief: Depression improved within one week of the full dose and was still improved three months later. The improvement was large enough to be considered clinically meaningful.
• Less anxiety: Anxiety improved one week after treatment and remained lower at the three-month follow-up.
• Fewer non-motor symptoms: Symptoms such as fatigue, sleep problems, and low motivation improved substantially, and the gains held at one month.
• Encouraging motor changes: Participants reported easier movement in daily activities, and clinician exams showed modest improvements. These changes exceeded what researchers consider clinically meaningful.
• Sharper thinking: Participants performed better on tests of learning, working memory, and mental flexibility, which is the ability to adapt when circumstances change.
• Improvement noticed at home: Care partners reported fewer mood and behavioral symptoms and less related distress, lasting at least three months.

Every participant agreed the treatment was helpful, and all said they would recommend it to others. Several described feeling better able to adapt to the challenges of living with Parkinson's.

Why Might Psilocybin Help With Parkinson's Symptoms?

Researchers are still exploring how psilocybin works, but there are several promising theories. Psilocybin appears to promote neuroplasticity, the brain's ability to form new connections. It may also reduce inflammation and influence brain networks connected to both serotonin and dopamine, the chemical messengers most affected by Parkinson's.

Another possibility is that improving mood itself may help the body. Depression places stress on the brain and body over time, so easing it could support better overall functioning. The researchers note that larger studies, including brain imaging and biomarker research, will help clarify which of these explanations is correct.

What This Means for People Living With Parkinson's Disease

This was a small pilot study without a placebo group, so the next step is larger, randomized controlled trials to confirm the results. Even so, it marks an important first step. It shows that psilocybin therapy can be delivered safely to people with Parkinson's in a carefully supervised setting, and that the potential benefits may extend well beyond mood.

For people living with Parkinson's and the depression or anxiety that often comes with it, this research offers genuine reason for optimism. Treatment options for these symptoms have been limited for a long time, and this study opens a promising new path. With careful preparation, medical oversight, and compassionate support, psilocybin-assisted therapy may help people with Parkinson's feel more like themselves again.

Read the Study: Bradley ER, Sakai K, Fernandes-Osterhold G, et al. Psilocybin therapy for mood dysfunction in Parkinson's disease: an open-label pilot trial. Neuropsychopharmacology. 2025;50:1200–1209. https://doi.org/10.1038/s41386-025-02097-0