Apathy and Depression in Parkinson Disease

Is apathy in patients with Parkinson disease (PD) merely a symptom of depression or a core symptom of PD itself? In the July issue of Neurology, researchers from the University of Florida surveyed patients with PD, a population known to exhibit high rates of both depression and apathy, and patients who had dystonia, another subcortical disorder. Kirsch-Darrow and colleagues administered several mood questionnaires to 80 patients with PD and 20 patients with adult-onset dystonia.

The researchers found a higher frequency of apathy in patients with PD (51%) than in patients with dystonia (20%), as well as higher scores on the Apathy Evaluation Scale, while patients in the 2 groups had similar frequencies of depression. When the results were analyzed to determine the number of patients who exhibited apathy only, depression only, or both depression and apathy, the frequency of apathy alone was approximately 30% in the PD cohort, whereas no patients with dystonia exhibited only apathy.