Relapse of Depression in Primary Care: Rate and Clinical Predictors

OBJECTIVE: To determine the clinical predictors and rate of relapse for major depression in primary care. DESIGN: A cohort study of subjects in 2 randomized trials of depressed patients diagnosed and prescribed antidepressant medicine by primary care physicians. Baseline, 7-month, and 19-month assessments were conducted. SETTING: A large primary care clinic of a staff-model health maintenance organization. PATIENTS: Two hundred fifty-one primary care patients who did not satisfy Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition (DSM-III-R) criteria for major depression at 7 months. MAIN OUTCOME MEASURES: Relapse was defined as (1) satisfying DSM-III-R criteria for major depression at 19 months, or (2) reporting an interval episode of 2 weeks or more of depressed mood and symptoms between 7 and 19 months. Predictors examined included demographic characteristics, medical comorbidity, disability, and psychological symptoms. Depressive symptoms were measured by Inventory of Depressive Symptoms and Hopkins Symptoms Checklist. RESULTS: Of the patients, 37.1% reported relapse of depression in the 12-month relapse-risk period. The 2 major risk factors associated with relapse were (1) persistence of subthreshold depressive symptoms 7 months after the initiation of antidepressant therapy (odds ratio, 3.3; 95% confidence interval, 2.74-3.93) and (2) history of 2 or more episodes of major depression, or chronic mood symptoms for 2 years (odds ratio, 2.1; 95% confidence interval, 1.41-2.76). Patients with both risk factors were approximately 3 times more likely to relapse than patients with neither. CONCLUSIONS: The relapse rate among primary care patients treated for depression approached that of specialty samples, with more than one third reporting relapse in 1 year. Clinical characteristics can help target high-risk patients for relapse prevention efforts.