Improving recognition of common mental health disorders in Cambodia: Validation of the PHQ-9 and GAD-7 and development of a brief mental health screener

Low- and middle-income countries (LMICs) bear 80% of the burden from common mental health disorders like depression and anxiety. One LMIC, Cambodia, has a mental health care gap due to history of genocide and civil war, persistent poverty, and under-resourced mental health system. Collaborative care models can improve access to and quality of mental health care by integrating care into existing health care infrastructure. While tools like the PHQ-9 and GAD-7 are widely used to detect unmet mental health needs and provide measurement-based care, their validity has not been established for many LMICs. We therefore sought to validate the PHQ-9 and GAD-7 and develop a brief mental health screener in the Cambodian context. This study was guided by an advisory committee of local mental health, health care, social work, and public health policymakers, practitioners, and researchers. The PHQ-9, GAD-7, and C-SSI were used to identify possible screening items and the HSCL and HTQ were used as criterion instruments to detect depression, anxiety and trauma. Pearson’s correlation was used to assess validity and k-fold cross validation was used to identify which combination of items were most predictive of mental health disorders. Among 498 patients (mean(SD) age 51(12.8) years, 48.6% women, 74.4% married), 19% and 13% screened positive for depression and for anxiety using the PHQ-9 and the GAD-7, respectively. Both the PHQ-9 and GAD-7 were strongly correlated with the HSCL and HTQ. The combination of two PHQ-9 items (sleep, worthlessness) and one GAD-7 item (nervousness) most accurately predicted mental health conditions (AUC = 0.980). The PHQ-9 and GAD-7 were valid in Cambodia, and we identified several items to screen for emotional distress. We are currently using these tools in a collaborative care model pilot in urban and rural settings and welcome others application to support Cambodian mental health equity.