Depression as a Risk Factor for Impulse Control Disorders in Parkinson Disease

To longitudinally evaluate the role of depression in the development of impulse control disorders (ICDs) in Parkinson disease (PD) patients.

Using data from the Parkinson's Progression Markers Initiative, we included PD patients without ICDs at baseline according to the Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease (QUIP). Patients were prospectively evaluated first quarterly and then biannually. Development of an ICD was defined as an increase in QUIP scores during follow-up. Using survival proportional hazard models, we studied the effect of baseline depression on ICD risk. We also evaluated this effect controlling for dopamine agonist use as a time-dependent variable and for other potential confounders.

Among 354 patients, 68 were depressed at baseline. The median follow-up was 4.08 years. Depression at baseline was associated with higher ICD risk (hazard ratio [HR] = 1.96, 95% confidence interval [CI] = 1.32-2.9, p < 0.001). This risk remained significant after controlling for dopamine agonist use (HR = 1.97, 95% CI = 1.33-2.9, p < 0.001), which was also independently linked to ICD development (HR = 1.87, 95% CI = 1.3-2.7, p < 0.001). Therefore, depressed patients faced an even higher ICD risk when receiving dopamine agonists. Controlling for multiple potential confounders did not alter these results.

Depression predisposes to the development of ICDs in PD. This risk is magnified by dopamine agonists. Dopamine agonists should thus be used cautiously in depressed PD patients. ANN NEUROL 2019;86:762-769.