Validity and accuracy of the Whooley questions to identify symptoms of depression in Norwegian postpartum women

Abstract

Introduction: Screening for postnatal depression is widely acknowledged as an important public health initiative. The Whooley case-finding questions are well suited for screening purposes in primary health care settings, as the instrument is quick and easy to administer. However, the validity and diagnostic accuracy among postpartum women remain unclear. The purpose of the present study was to evaluate the validity and diagnostic accuracy of the Whooley questions compared to the Edinburgh postnatal depression scale (EPDS) in a community sample of postpartum women in Norway. The diagnostic accuracy of the Whooley questions was examined across different EPDS thresholds and compared to the measures of related constructs, including symptoms of childbirth-related post-traumatic stress disorder (PTSD) and anxiety. Material and Methods: Cross-sectional data were collected through an online questionnaire by postpartum women (0–52 weeks postpartum), recruited via social media, well-baby clinics, and other locations frequently visited by postpartum women. In total, 1154 women participated. The diagnostic accuracy of the Whooley questions was compared to three commonly used EPDS cutoffs (≥10, ≥12, and ≥13). Results: The sensitivity of the Whooley questions relative to the EPDS was high and increased with higher thresholds for defining depression, correctly identifying 89% (EPDS ≥10), 96% (EPDS ≥12), and 97% (EPDS ≥13) of cases. Specificity was somewhat lower, at 0.82 (EPDS ≥10), 0.77 (EPDS ≥12), and 0.75 (EPDS ≥13). Positive predictive values were low, whereas negative predictive values were excellent, ranging from 0.97 (EPDS ≥10), through 0.99 (EPDS ≥12) to 1.00 (EPDS ≥13), increasing with higher thresholds. Convergent and divergent validity were supported by strong correlations with EPDS scores and moderate correlations with symptoms of childbirth-related PTSD and anxiety. Conclusions: The Norwegian version of the Whooley questions demonstrates strong psychometric properties, supporting their usefulness as a case-finding tool for depression among postnatal women.