Validation of the Patient Health Questionnaire (PHQ)-9 for prenatal depression screening

Abstract

The study was designed to validate the Patient Health Questionnaire (PHQ-9) for depression risk identification among pregnant women. Pregnant women were routinely administered the Prenatal Risk Overview, a comprehensive psychosocial screening interview, which included the PHQ-9, at their prenatal intake appointment at three community clinics. Study participants completed the Structured Clinical Interview for DSM-IV (SCID) at a later appointment. PHQ-9 risk classifications were cross-tabulated with SCID diagnostic categories to examine concordance, sensitivity, specificity, and positive and negative predictive values. The study sample included 745 women. Prevalence of a current major depressive episode was 3.6%; an additional 7.0% were classified as meeting subdiagnostic criteria of three or more depressive symptoms. A PHQ-9 score cutoff of 10 yielded sensitivity and specificity rates of 85 and 84%, respectively, for a depression diagnosis and 75 and 88% for a subdiagnosis, respectively. Positive predictive value was higher for the expanded group (43%) than that of the diagnosis-only group (17%). The PHQ-9, embedded within a multidimensional risk screening interview, effectively identified pregnant women who met criteria for current depression. The moderate risk score cutoff also identified women with subdiagnostic symptom levels who may benefit from interventions to alleviate their distress and improve pregnancy outcomes.