CBT for psychosis in Parkinson's disease: A framework for how and why.

Psychosis is a serious comorbidity to Parkinson's disease associated with high levels of distress and disability but access to effective treatments remain limited, leading to high rates of emergency hospitalization. Here, we propose a new framework for how cognitive behavioural therapy (CBT) may be used to treat Parkinson's disease psychosis. We note specific adaptions, including aims that focus on reducing distress and disability and extending quality of life; tailored psychoeducation; assessment and formulation that additionally includes disease course, medication effects and side-effects, and Parkinson's specific social factors; addressing anxiety and depression alongside cognitive appraisals for the types of psychotic symptoms more common in Parkinson's disease; appropriate reality testing sensitive to disease progression; and trigger monitoring and management for hallucinations and delusions that carefully distinguishes this from avoidant coping. We review preliminary case study-level evidence for the successful use of CBT for Parkinson's disease psychosis and suggest a road map for its formal evaluation before integration into evidence-based healthcare.