Increased risk of depressive and anxiety disorders in relatives of patients with Parkinson disease

CONTEXT: Relatives of patients with Parkinson disease (PD) have an increased risk of PD and other neurologic disorders; however, their risk of psychiatric disorders remains uncertain. OBJECTIVE: To study the risk of depressive disorders and anxiety disorders among first-degree relatives of patients with PD compared with first-degree relatives of controls. DESIGN, SETTING, AND PARTICIPANTS: In a population-based, historical cohort study, we included 1000 first-degree relatives of 162 patients with PD and 850 first-degree relatives of 147 controls. Both patients with PD and controls were representative of the population of Olmsted County, Minnesota. MAIN OUTCOME MEASURES: Documentation of psychiatric disorders was obtained for each relative separately through a combination of telephone interviews with the relatives (or their proxies) and review of their medical records from a records-linkage system (family study method). Psychiatric disorders were defined using clinical criteria from the DSM-IV or routine diagnoses. RESULTS: We found an increased risk of several psychiatric disorders in first-degree relatives of patients with PD compared with first-degree relatives of controls (hazar