A New (Old) Treatment Option for Depression in Parkinson's Disease
Abstract
Parkinson's disease is the most common neurodegenerative disease after Alzheimer's disease, affecting 1%–4% of people by age 80 (1). Although it is defined by motor signs, the symptoms that most impair the lives of patients—and their caregivers—are psychological symptoms, including depressed mood (2). In clinical settings, about 25% of patients with Parkinson's disease have a major depressive syndrome, and about half have clinically important depressive symptoms (2, 3). (The terminology is awkward, because according to DSM-IV-TR, a major depressive episode cannot be diagnosed if the symptoms are directly caused by a nonpsychiatric illness such as Parkinson's disease, and there is substantial evidence that the Parkinson's disease process does directly cause at least some of the depression in these patients [2]).The increased rate of depression in Parkinson's disease begins before motor impairment is evident, and it is not explained by a psychological reaction to disability (2). Depression in Parkinson's disease (4) is demonstrably different from ordinary major depression in terms of sex ratio, age, symptom profile, comorbidity, and chronicity. Pharmacotherapy for depression in Parkinson's disease entails special concerns related to side effects and drug-drug interactions. The cognitive deficits present in a substantial fraction of Parkinson's disease patients raise questions