Diagnosing ICD-10 depressive episodes: superior criterion validity of the Patient Health Questionnaire.

Background: Diagnosing and monitoring depression in primary care remains an issue of significant public health concern. Clinicians and researchers need to know if any one screening instrument is superior to the others in diagnosing ICD-10 depressive episodes. This study aimed to examine the criterion validity for diagnosing ICD-10 depressive episodes of the Patient Health Questionnaire (PHQ) in comparison with 2 well-established instruments, the Hospital Anxiety and Depression Scale (HADS), and the WHO Well-Being Index 5 (WBI-5).