Diagnosis and Treatment of Depression in Parkinson’s Disease

Abstract

Depression and anxiety are the most common and frequently disabling psychiatric conditions that accompany Parkinson’s disease (PD). Although James Parkinson, in his original report of six patients, wrote that the “senses and intellect being uninjured” (1), he still used descriptions like “melancholy” and “unhappy sufferer.” In early 1920s, some authors argued that “abnormal psychic functioning” was a part of the disease process and that “the mental set was always depressive” (2). Nowadays, it is widely accepted that, despite discrepancies in patient selection, inconsistent definitions of depression, and different methods of assessment, a considerable risk of depression appears to accompany PD. Depressive symptoms in parkinsonian patients have been classified as “organic mood syndrome” in the Diagnostic and Statistical Manual of Mental Disorders, third edition, revised (DSM-IIIR) and as “mood disorder due to a general medical condition” in DSM-IV. Although the exact etiology of depression in PD is unclear, available evidence suggests that biochemical changes, psychosocial factors, and situational stressors may all contribute to its development (3). Finally, although major depression (MD) may occur in PD, studies indicate that the majority of depressed parkinsonians have less severe forms such as minor depression, dysthymic disorder, and subsyndromal forms (4–6).