Psychometric validation of the 15-item Patient Health Questionnaire – Anxiety and Depression Scale (PHQ-ADS) to assess psychological distress in breast cancer survivors.

Psychological distress persists amongst breast cancer survivors, so reliable assessment of symptoms is essential. The Patient Health Questionnaire Anxiety and Depression Scale (PHQ-ADS) is a composite measure of depression and anxiety and has been used to measure distress. This study aimed to evaluate the psychometric properties of the PHQ-ADS within breast cancer survivors. Breast cancer survivors (N = 280) were recruited online and followed up at 12-months. Depression (PHQ-8) and anxiety (GAD-7) items formed the composite PHQ-ADS score. Additional measures included: distress thermometer (convergent validity), fear of cancer recurrence and COVID distress (discriminant validity), and self-compassion (predictive validity). Confirmatory factor analysis (CFA) using weighted least squares mean and variance adjusted estimation was undertaken. One, two, and bifactor models underlying the PHQ-ADS were evaluated. The bifactor model had the most appropriate model fit overall. Omega hierarchical for the general distress factor was 0.914, accounting for 82% of explained variance. This suggests the PHQ-ADS is sufficiently unidimensional to warrant use of a total composite score. The PHQ-ADS demonstrated strong convergent and moderate discriminant validity. Self-compassion was an independent predictor of distress at 12-months. The PHQ-ADS is a valid measure for psychological distress in breast cancer survivors prescribed hormone therapy. • The PHQ-ADS shows good psychometric properties in breast cancer survivors. • Sufficient unidimensionality shown, suggesting suitability of total distress score. • The PHQ-ADS shows good convergent validity and adequate discriminant validity. • Self-compassion explained 7% unique variance in distress at 12 months. [ABSTRACT FROM AUTHOR]