OBJECTIVES: To evaluate the performance of the Mental Component of the Short-Form 12 Health Survey, Version 1(SF-12v1), as a screening measure of depressive disorders. METHODS: Data come from the European Study of the Epidemiology of Mental Disorders (ESEMeD), a cross-sectional survey carried out on representative samples of 21,425 individuals from the noninstitutionalized adult general population of six European countries (response rate = 61.2%). The SF-12 was administered and scored according to three algorithms: the "original" method (mental component summary of SF-12 [MCS-12]), the RAND-12 (RAND-12 Mental Health Composite [RAND-12 MHC]), and the Bidemensional Response Process Model 12 mental health score (BRP-12 MHS), based on a two-factor Item Response Theory graded response model. Thirty-day and 12-month depressive disorders (major depressive episode or dysthymia) were assessed with the Composite International Diagnostic Interview, Version 3.0, by using Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria. Receiver operating characteristic curves analysis was carried out, and optimal cutoff points maximizing balance between sensitivity (SN) and specificity (SP) were chosen for the three methods. RESULTS: Prevalence of 30-day and 12-month depressive disorders in the overall sample was 1.5% and 4.4%, respectively. The area under the curve for 30-day depressive disorders was 0.92, and it decreased to 0.85 for 12-month disorders, regardless of the scoring method. Optimal cutoff for 30-day depressive disorders was 45.6 (SN = 0.86; SP = 0.88) for the MCS-12, 44.5 for the RAND-12 MHC (SN = 0.87, SP = 0.86), and 40.2 for the BRP-12 MHS (SN = 0.87, SP = 0.87). The selected 12-month cutoffs for MCS-12 and RAND-12 MHC were between 4.2 and 5.8 points below the general population means of each country, with SN range 0.67 to 0.78 and SP range 0.77 to 0.87.CONCLUSIONS: The SF-12 yielded acceptable results for detecting both active and recent depressive disorders in general population samples, suggesting that the questionnaire could be used as a useful screening tool for monitoring the prevalence of affective disorders and for targeting treatment and prevention.