Objective: To test the effects of a novel cognitive-behavioral therapy (CBT)-based intervention delivered by a nurse therapist to patients with Parkinson disease (PD) with clinically significant impulse control behaviors (ICB).
Methods: This was a randomized controlled trial comparing up to 12 sessions of a CBT-based intervention compared to a waiting list control condition with standard medical care (SMC). A total of 27 patients were randomized to the intervention and 17 to the waiting list. Patients with a Mini-Mental State Examination score of <24 were excluded. The coprimary outcomes were overall symptom severity and neuropsychiatric disturbances in the patients and carer burden and distress after 6 months. Secondary outcome measures included depression and anxiety, marital satisfaction, and work and social adjustment in patients plus general psychiatric morbidity and marital satisfaction in carers.
Results: There was a significant improvement in global symptom severity in the CBT intervention group vs controls, from a mean score consistent with moderate to one of mild illness-related symptoms (χ(2) = 16.46, p < 0.001). Neuropsychiatric disturbances also improved significantly (p = 0.03), as did levels of anxiety and depression and adjustment. Measures of carer burden and distress showed changes in the desired direction in the intervention group but did not change significantly. General psychiatric morbidity did improve significantly in the carers of patients given CBT.
Conclusions: This CBT-based intervention is the first to show efficacy in ICB related to PD in terms of patient outcomes. The hoped-for alleviation of carer burden was not observed. The study demonstrates the feasibility and potential benefit of a psychosocial treatment approach for these disturbances at least in the short term, and encourages further larger-scale clinical trials.
Classification of evidence: The study provides Class IV evidence that CBT plus SMC is more effective than SMC alone in reducing the severity of ICB in PD, based upon Clinical Global Impression assessment (χ(2) = 16.46, p < 0.001): baseline to 6-month follow-up, reduction in symptom severity CBT group, 4.0-2.5; SMC alone group, 3.7-3.5.