A Brief Depression Screening Tool for Perinatal Clinical Practice: The Performance of the PHQ-2 Compared with the PHQ-9

Introduction There is ongoing interest in using brief screening instruments to identify perinatal depression in clinical practice. One ultra-brief screening instrument for depression is the Patient Health Questionnaire-2 (PHQ-2), but thus far its accuracy in perinatal clinical practice has been barely researched. In the present study, we aimed to assess the screening accuracy of the PHQ-2 against the Patient Health Questionnaire-9 (PHQ-9) in a large sample of perinatal women. Method A total of 1155 consecutive women attending 11 health care centers throughout Italy completed the PHQ-9 (which includes the PHQ-2) during pregnancy (27-40 weeks) or postpartum (1-13 weeks). Sensitivity, specificity, positive predictive value, negative predictive value, likelihood ratio positive, likelihood ratio negative, and overall accuracy were calculated using cut points 3 or greater and 2 or greater. Results During pregnancy, PHQ-2 greater than or equal to 3 revealed low sensitivity (38.4%-44.7%) but high specificity (97.8%-99.3%). In postpartum, it revealed moderate sensitivity (56.9%-70.6%), high specificity (95.8%-99.8%), and fair overall accuracy in pregnancy (70%). The alternative threshold greater than or equal to 2 revealed very high sensitivity (pregnancy: 92.1%-95.2%; postpartum: 87.1%-95.2%), moderate specificity (pregnancy: 78.1%-83.2%; postpartum: 68.8%-81.1%) and good overall accuracy, both during pregnancy (87%) and postpartum (84%). Discussion The PHQ-2 provided acceptable accuracy for screening for depression compared with the PHQ-9. In perinatal screening practice, a threshold of 2 or greater should be preferred as this ensures high sensitivity, missing only approximately 6% to 8% of cases, and a false-positive rate (percentage of women classified as affected with depressive symptoms when they are not) of 19% to 25%.