The outcome of depressive disorders in neurology patients: a prospective cohort study

Background: In a previous prospective study of 300 consecutive new attenders at neurology outpatient clinics, depressive disorders were diagnosed in 119 patients (40%) and major depressive disorder in 77 (26%). Objective: To describe the eight month outcome of depression in this cohort. Methods: Patients were reinterviewed eight months after their baseline assessment. Mental state was examined using the primary care evaluation of mental disorders (PRIME-MD) interview and the hospital anxiety and depression (HAD) self rating scale. Health status was measured using the medical outcome study 36 item short form scale (SF-36). Results: Of the original cohort of 300, 226 (75%) participated in the follow up. Among them, 88 had a depressive disorder at baseline and 69 (78%) of those were still depressed at follow up; 54 had major depression at baseline and 46 (85%) of those still had a major depressive disorder at follow up. Among the 138 patients who had no depression at baseline, 20 new major depressive disorders had developed by the time of follow up. Resolution of major depressive disorders was associated with an improvement in health status. Conclusions: Most depressive disorders detected in neurology outpatients persist at an eight month follow up, and a substantial number of new cases arise. Resolution of depressive disorders, particularly major depressive disorder, is associated with an improvement in health status.