The WHO-5 Wellbeing Index performed the best in screening for depression in primary care.

D e s c r i p t i o n o f t e s t s a n d d i a g n o s t i c s t a n d a r d Before being seen by a physician, patients completed 3 screening questionnaires: the depression module of the Brief Patient Health Questionnaire (PHQ-9), the General Health Questionnaire, and the World Health Organization (WHO) Wellbeing Index (WHO-5). Physicians treating the patients completed an encounter form to record a clinical assessment, blinded to the screening results. Within 6 days of their visit, patients were contacted via telephone by a psychologist, who was blinded to the screening results and physician assessment, for a standardized psychiatric interview using the Composite International Diagnostic Interview.