Further validation of the postpartum depression screening scale

Background: Up to 50% of ail cases of postpartum depression go undetected. The Edinburgh Postnatal Depression Scale (EPDS) has been the only instrumen t available that was specifically designed to screen for this mood disorder . None of the items on the EPDS, however, are written in the context of new motherhood. Objective: The purpose of this study was to further assess the construct va lidity of the newly designed Postpartum Depression Screening Scale (PDSS) a long with its sensitivity, specificity, and predictive values. Method: A total sample of 150 mothers within 12 weeks postpartum participat ed in the study. Each mother completed in random order three questionnaires : The PDSS, EPDS, and The Beck Depression Inventory-ii (BDI-II). immediatel y after completing these three questionnaires, each woman was interviewed b y a nurse psychotherapist using the Structural Clinical Interview for DSM-I V Axis 1 Disorders. Results: Twelve percent (n = 18) of the mothers were diagnosed with major p ostpartum depression, 19% (n = 28) with minor postpartum depression, and 69 % (n = 104) with no depression. The PDSS was strongly correlated with both the BDI-II (r = 0.81) and the EPDS (r = 0.79). The ability of the PDSS to e xplain variance in diagnostic classification of postpartum depression above that explained by the BDI-II and EPDS (i.e., incremental validity) was ass essed using hierarchical regression. After explaining variance in group cla ssification by the other two depression instruments, the PDSS explained an additional 9% of the variance in depression diagnosis. Using receiver opera ting characteristic (ROC) curves, a PDSS cut-off score of 80 (sensitivity 9 4% and specificity 98%) is recommended for major postpartum depression and a cut-off score of 60 (sensitivity 91% and specificity 72%) for major or mi nor depression. Conclusion: Based on the results of this psychometric testing, the PDSS is considered ready for use in routine screening of mothers.