The Patient Health Questionnaire-9 (PHQ-9; R. L. Spitzer, K. Kroenke, J. B. W. Williams, & The Patient Health Questionnaire Primary Care Study Group, 1999), modified to ask about the worst period of depression lifetime, was validated against lifetime mood disorder diagnoses established by the Structured Clinical Interview for DSM-IV (SCID; M. B. First, R. L. Spitzer, M. Gibbon, & J. B. W. Williams, 2001) in 526 participants. PHQ-9 dichotomous scores corresponded highly with major depressive episode (MDE) Criterion A, MDE, and major depressive disorder (MDD), odds ratios = 9.5, and area under the receiver operating characteristic curve (AUC) = 0.84. The continuous scale score was higher in participants who did (M = 17.14, SD = 7.36) than in those who did not (M = 6.05, SD = 6.29) meet MDE Criterion A, t(524) = 18.09, p less than 0.001; was correlated with number of MDE Criterion A symptoms, r(525) = 0.67, p less than 0.001; and detected MDE Criterion A (AUC = 0.88). The PHQ-9 as a lifetime measure may be used to complement or replace more costly interview assessments.