Psychedelic-assisted psychotherapy (PAP) shows promise for treating mental health conditions like substance use disorders and depression, yet the role of the psychotherapy component itself has received little empirical scrutiny. This review examines current debates over whether PAP involves full psychotherapy or merely psychological support, and summarizes existing clinical trial models and theoretical frameworks. It draws lessons from traditional psychotherapy research, advocating for standardized treatment manuals, clear provider eligibility criteria, measurement of established mechanisms of change, and optimized trial designs such as dismantling studies and comparative efficacy trials. The authors argue that PAP is a distinct, integrative, transdisciplinary intervention requiring further research into its psychotherapeutic components to inform best practices and federal guidelines.
In an open-label pilot trial, 12 people with mild to moderate Parkinson's disease plus depression or anxiety received psilocybin (10 mg then 25 mg) with psychotherapy. No serious adverse events occurred, and no worsening of Parkinson's symptoms was observed. Non-motor and motor symptoms improved, and gains in some cognitive domains were sustained one month later. Depression and anxiety scores improved to a clinically meaningful degree and remained improved three months after dosing. These first results in any neurodegenerative disease suggest psilocybin therapy for Parkinson's disease warrants further study.