Psychometric Validation of PHQ-9 and GAD-7 in Filipino Migrant Domestic Workers in Macao (SAR), China

There are 500,000 female Filipino domestic workers worldwide. However, there are no validated instruments to assess common mental disorders in this population. The Patient Health Questionnaire (PHQ-9) and Generalized Anxiety Disorder (GAD-7) are brief measures that could be effective screeners for depression and anxiety in domestic workers. This study aims to establish reliability and validity of the Filipino versions of the PHQ-9 and GAD-7. In Study 1, 131 domestic workers completed the PHQ-9, GAD-7, and other questionnaires with a test-retest interval of 10 days. Convergent validity was examined using measures of posttraumatic stress disorder, direct exposure to traumatic events, and rumination. Discriminant validity was assessed using measures of discrimination, pain, social support, and indirect exposure to traumatic events. In Study 2, criterion validity was established with another sample of domestic workers (N = 100) using clinician-administered Mini International Neuropsychiatric Interviews. Receiver operating characteristic (ROC) curve analysis was performed to evaluate diagnostic efficiency. Results showed acceptable and high internal consistency for PHQ-9 and GAD-7, respectively. Both had acceptable test-retest reliability. Convergent and discriminant validity were also established. ROC curve results demonstrated that optimal cut scores for PHQ-9 and GAD-7 are 6 and 7, respectively. The Filipino versions of PHQ-9 and GAD-7 are reliable and valid for use among Filipino domestic workers.