Depression and anxiety can add substantially to the burden of Parkinson’s disease. They deserve assessment and treatment alongside movement difficulties, sleep problems and changing independence. Early investigation of psilocybin has focused on these mood symptoms, with additional exploratory observations of motor and cognitive function. It has not demonstrated that psilocybin slows Parkinson’s disease or restores lost nerve cells.
A small open-label trial found improved mood in carefully selected people with mild-to-moderate Parkinson’s disease. Its motor and cognitive findings are preliminary. The absence of serious adverse events in 12 participants is useful feasibility information, not a general safety guarantee for people with Parkinson’s disease.
On this page
- Mood symptoms are part of the clinical burden
- The first open-label clinical findings
- Mood, movement and disease progression are different outcomes
- Why a better motor score does not prove neuroprotection
- Cognitive findings require equal restraint
- Patient selection and medication safety
- Care continues beyond an experimental intervention
- The next clinical questions
Mood symptoms are part of the clinical burden
Parkinson’s disease is associated with impaired dopamine signalling and progressive difficulties that can include slowness, stiffness, tremor and impaired balance. Its effects extend beyond movement: depression, sleep disturbance and difficulties with speech or swallowing may also occur. Existing treatments can help symptoms, but there is currently no cure.1
Low mood should not be dismissed as an inevitable response to a neurological diagnosis. At the same time, fatigue, slowed movement, reduced facial expression and sleep disturbance can complicate the interpretation of a depression rating. An assessment needs the person’s account of mood, pleasure, anxiety and function, interpreted alongside the neurological presentation.
Loss of motivation, cognitive change and depression are clinically distinct concerns even when they coexist. The practical questions include what has changed, when symptoms occur, and how they affect daily activities. Treatment goals might include renewed social engagement or less distress during fluctuations in mobility; neither goal requires an assertion that the underlying neurodegeneration has reversed.
The first open-label clinical findings
A 2025 pilot enrolled 12 people with mild-to-moderate Parkinson’s disease and a diagnosis of depression, anxiety or both. Participants received two psilocybin sessions within a programme that included seven psychotherapy meetings. There was no placebo or other comparison group, and participants and clinicians knew the treatment being given.2
At three months after the second session, the mean depression score on the Montgomery–Åsberg Depression Rating Scale had fallen by 9.3 points, and the mean Hamilton Anxiety Rating Scale score had fallen by 3.8 points. Anxiety improvement was not statistically significant at the earlier one-month assessment, so the pattern was not uniformly significant across follow-up. These changes are encouraging, but an uncontrolled before-and-after comparison cannot establish how much was caused by psilocybin, psychotherapy, expectation or other influences.2
No serious adverse events or need for medical intervention were reported. However, 10 of the 12 participants experienced treatment-emergent adverse events, commonly anxiety, nausea or increased blood pressure. The accurate interpretation is that treatment appeared feasible in this selected, closely supported sample—not that administration was free of adverse effects.2
The study evaluated a combined intervention. Its design cannot determine the separate contributions of the drug, preparation, therapeutic attention and follow-up. Nor does it identify an optimal number of sessions or demonstrate that repeated treatment remains safe over a longer period.
Mood, movement and disease progression are different outcomes
| Outcome | Pilot observation | Interpretive limit |
|---|---|---|
| Depression and anxiety | Average symptom ratings improved; mood follow-up extended to three months. | No control group established a treatment-specific effect. |
| Motor and daily-life ratings | Several scores improved at the one-month assessment. | Exploratory short-term changes do not establish slower disease progression. |
| Cognitive testing | Some tasks improved; others did not. | Small numbers, repeated testing and multiple outcomes limit confidence. |
| Neurodegeneration | Disease modification was not demonstrated. | No evidence of restored dopamine neurons or prevention of dementia was established. |
The Movement Disorder Society Unified Parkinson’s Disease Rating Scale separates non-motor experiences, motor experiences of daily living, the motor examination and motor complications. Improvement in one component does not mean improvement in all four. In the pilot, motor-complication scores did not show a statistically significant change at one month, despite favourable findings in other components.2
Timing also matters. The motor and cognitive assessments extended to one month after treatment, whereas mood assessments continued to three months. Describing the motor findings as a demonstrated three-month benefit would overstate the observation period.
Why a better motor score does not prove neuroprotection
A short-term change in performance can have several explanations. Reduced distress, altered attention, greater willingness to move, expectation and ordinary variation in symptoms may affect how a person performs. Without a comparison group, these possibilities cannot be separated confidently from a direct pharmacological effect.
The distinction is especially relevant in Parkinson’s disease, where placebo responses can affect measured outcomes. The pilot authors identify both expectation and the open-label design as important limitations. A credible controlled study needs consistent assessment conditions and independent outcome evaluation to reduce the risk that hoped-for improvement influences measurement.2
A disease-modifying claim requires evidence about the course of the illness over time, with an appropriate comparator and measures capable of distinguishing symptomatic relief from altered progression. General findings about psychedelic-related plasticity do not supply that evidence in people with Parkinson’s disease. Neuroplasticity is not synonymous with replacing lost neurons.
Cognitive findings require equal restraint
The pilot reported improvements on some measures of learning, spatial working memory and reversal learning. Planning and reaction-time measures did not show significant improvement. It would therefore be inaccurate to describe the results as a general restoration of cognition.2
Repeated cognitive testing introduces an additional question: does a person perform better because the underlying ability has improved, because the task is more familiar, or because mood and engagement have changed? Larger controlled samples are needed to estimate these contributions. Exploring several outcomes can generate valuable hypotheses, but it also makes independent confirmation particularly important.
People with significant cognitive impairment were excluded from the pilot. Its findings cannot establish safety or effectiveness in Parkinson’s disease dementia, nor show that treatment prevents future cognitive decline.
Patient selection and medication safety
Eligibility excluded serious cardiovascular complications, significant cognitive impairment, a history of mania or a primary psychotic disorder, and current psychosis involving loss of insight. Several medication groups were also excluded, including serotonin reuptake inhibitors, monoamine oxidase inhibitors, dopamine agonists and anticholinergics. These restrictions substantially narrow the population to which the results apply.2
The first three participants were not receiving dopaminergic treatment for motor symptoms. The subsequent nine continued a stable carbidopa–levodopa regimen throughout the study, including the psilocybin sessions. This is relevant evidence about that particular supervised combination; it does not establish safety with every Parkinson’s medication or with more complex regimens.2
A research exclusion is not an instruction to stop treatment. NICE advises against abrupt withdrawal of antiparkinsonian medicines because of potentially severe consequences, including acute akinesia and neuroleptic malignant syndrome. Medication changes should be coordinated with the clinician responsible for Parkinson’s care.3
Practical safety assessment also needs to address mobility, blood pressure, assistance with transfers and the person’s ability to understand and communicate during an altered state. Intense psychological effects occur in a body that may already have movement or autonomic difficulties. A reassuring psychiatric assessment alone is insufficient to establish physical suitability.
Care continues beyond an experimental intervention
Parkinson’s management may involve medication review, physiotherapy, occupational therapy and speech and language support according to need. Depression and anxiety warrant their own assessment and treatment within that continuing care. A potential mood intervention should be judged by whether it improves daily life while preserving access to neurological and psychiatric treatment.3
Psychological treatment already has controlled evidence in this population. A trial of 72 people compared telephone-delivered cognitive behavioural therapy plus usual care with usual care alone. Depression improved more with CBT, with gains maintained during six-month follow-up; anxiety and quality-of-life outcomes also favoured the intervention. This was not a comparison with psilocybin, but it demonstrates that mood treatment need not wait for experimental psychedelic approaches.4
Follow-up should consider the patient’s own goals as well as symptom scales. Greater participation, improved relationships or less distress may be valuable even if motor disease is unchanged. Conversely, a positive account of a session does not remove the need to investigate new confusion, hallucinations, falls or worsening mood.
Caregiver observations can provide useful context, with the patient’s agreement. They should supplement rather than replace the person’s account. Support needs and treatment burden also matter: repeated visits, transport, supervision and recovery time can affect whether an intervention is practical for someone with fluctuating mobility.
The next clinical questions
Controlled trials need to establish the size and durability of any antidepressant or anxiolytic effect, the frequency of adverse events and the contribution of psychological support. They should also clarify outcomes in more representative populations, including people taking common medications or living with greater physical complexity.
Motor and cognitive questions require their own prespecified outcomes and adequate follow-up. Improvement in mood should not be used as a substitute for evidence of neuroprotection, and an exploratory motor signal should not obscure the value of treating distress. At present, the strongest rationale for further investigation concerns mood symptoms in selected patients; broader claims about reversing Parkinson’s disease remain unsupported.
References
- US National Library of Medicine. Parkinson’s Disease. MedlinePlus; accessed 11 October 2026.
- 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. doi:10.1038/s41386-025-02097-0.
- National Institute for Health and Care Excellence. Parkinson’s disease in adults (NG71). Recommendations; accessed 11 October 2026.
- Dobkin RD, Mann SL, Gara MA, et al. Telephone-based cognitive behavioral therapy for depression in Parkinson disease: A randomized controlled trial. Neurology. 2020;94:e1764–e1773. doi:10.1212/WNL.0000000000009292.