This Phase 2 clinical trial investigates psilocybin as a novel treatment for depression in Parkinson's Disease (PD) patients. Depression is one of the most common non-motor symptoms in PD, affecting up to 50% of patients throughout the disease course. This trial represents a cutting-edge approach to addressing this unmet clinical need through psychedelic-assisted therapy.
| Parameter | Value |
|---|---|
| NCT Number | NCT06455293 |
| Status | Recruiting |
| Phase | Phase 2 |
| Sponsor | To be confirmed |
| Collaborators | To be confirmed |
| Intervention | Psilocybin |
| Purpose | Treatment of depression in PD |
| Study Type | Interventional |
| Estimated Enrollment | 40-60 participants |
| Study Design | Randomized, double-blind, placebo-controlled |
Psilocybin exerts its therapeutic effects through multiple interconnected mechanisms:
Psilocybin is a prodrug that is metabolized to psilocin, its active form. Psilocin acts as a partial agonist at serotonin 5-HT2A receptors, which are densely distributed in the prefrontal cortex and other brain regions involved in mood regulation. This receptor activation leads to:
The default mode network (DMN) is hyperactive in depression and anxiety states. Psilocybin has been shown to:
Research has demonstrated that psilocybin promotes neuroplasticity through:
Depression is the most common neuropsychiatric complication in PD:
Standard antidepressants face limitations in PD:
| Treatment | Limitations in PD |
|---|---|
| SSRIs | May worsen motor symptoms; delayed onset |
| SNRIs | Similar limitations; side effect burden |
| TCAs | Anticholinergic effects; cardiac toxicity |
| Dopamine agonists | May cause impulse control disorders |
Psilocybin offers several potential advantages for PD depression:
The trial employs a rigorous design:
Psychedelic-assisted therapy combines:
Key safety measures for PD patients:
| Measure | Description |
|---|---|
| Change in depression scores | Assessed using validated scales (e.g., BDI, MADRS) |
| Response rate | Percentage achieving clinically significant improvement |
| Remission rate | Proportion achieving symptom remission |
| Measure | Description |
|---|---|
| Motor symptom stability | UPDRS motor scores to ensure no worsening |
| Quality of life | PDQ-39 and general quality of life measures |
| Anxiety symptoms | GAD-7 or similar |
| Cognitive function | MoCA and neuropsychological testing |
| Sleep quality | PDSS and general sleep scales |
| Duration of effect | Long-term follow-up of antidepressant response |
This trial represents several important firsts:
If successful, this trial could:
Parkinson's Disease involves multiple neurotransmitter systems beyond dopamine:
PD involves chronic neuroinflammation, and psilocybin may address this through:
5-HT2A-mediated anti-inflammatory effects in glial cells
Modulation of microglial activation
Reduced pro-inflammatory cytokine production
Potential disease-modifying implications
Non-Motor Symptoms in PD
5-HT2A Receptor
Psilocybin's therapeutic effects in depression are primarily mediated through its activation of serotonin 5-HT2A receptors[1]. Upon ingestion, psilocybin is converted to psilocin, which exhibits high affinity for 5-HT2A receptors as a partial agonist[2]. This activation leads to downstream effects including:
Depression in PD is thought to involve both dopaminergic and serotonergic dysfunction[7]. While PD primarily affects dopaminergic neurons in the substantia nigra, serotonergic systems are also compromised, particularly in advanced disease[8]. The 5-HT2A receptor-mediated effects of psilocybin may address this serotonergic deficit while also promoting neural plasticity that could benefit motor and non-motor symptoms[9].
The trial targets patients with:
Psilocybin therapy for depression in PD typically involves[10]:
Psilocybin-assisted therapy has shown promise for treatment-resistant depression in general populations[11]. Potential benefits for PD patients include:
Safety considerations include[12]:
Depression in PD significantly impacts quality of life and may accelerate disease progression[13]. Treating depression may also improve:
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Kraehenmann, R. et al. (2015). Psilocybin induces changes in emotional processing. Journal of Psychopharmacology. 2015. ↩︎
Burn, D.J. (2012). Depression in Parkinson's disease. European Journal of Neurology. 2012. ↩︎
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Carhart-Harris, R.L. et al. (2016). Psilocybin for treatment-resistant depression. Lancet Psychiatry. 2016. ↩︎
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Schapira, A.H.V. et al. (2017). Non-motor features of Parkinson's disease. Nature Reviews Neurology. 2017. ↩︎