Cognitive-behavioral therapy in people with Parkinson's disease and caregivers: A mixed method systematic review on clinical applications and therapeutic outcomes

Abstract

Background Cognitive behavioral therapy (CBT) has emerged as a promising intervention in Parkinson's disease (PD), although the available evidence remains heterogeneous in design and quality. Objective The present mixed method systematic review aims to synthesize the evidence on CBT in people with PD (PwPD) and caregivers, focusing on clinical applications and therapeutic outcomes across symptom domains. Methods A systematic search of PubMed, Web of Science, Scopus and Cochrane databases was conducted for studies published between 1980 and 2025, following PRISMA guidelines. Eligible studies evaluated clinical applications and therapeutic outcomes of CBT-based interventions in PwPD and/or caregivers and included randomized controlled trials, observational studies, case series and single-case reports. Findings were synthesized narratively, and certainty of evidence was assessed using a simplified GRADE approach. Results Fifty-four studies met inclusion criteria. The most robust evidence was observed for depression, with several RCTs supporting the efficacy of CBT, resulting in moderate certainty of evidence. Evidence for anxiety and sleep disorders suggests potential benefit; however, certainty was low due to heterogeneity and small sample sizes. Evidence for impulse control disorders, cognitive outcomes, motor symptoms, and caregiver -related outcomes remain limited, with low to very low certainty, Effects on motor symptoms were inconsistent and likely indirect. Conclusions CBT represents a flexible and transdiagnostic intervention for treating non-motor symptoms in PwPD and for caregivers. While moderate-certainty evidence supports CBT use for depression, evidence for other domains remains limited. These findings should be interpreted with caution, and further large-scale, well designed RCTs are needed to strengthen the evidence base and clarify optimal therapeutic targets and delivery format.