Patient health questionnaire-9 as an effective tool for screening of depression among Indian adolescents

Detection of depression among adolescents in the primary care setting is of paramount importance, especially in resource-constrained countries such as India. This article discusses the diagnostic accuracy, reliability, and validity of the Patient Health Questionnaire-9 (PHQ-9) when pediatricians use it among Indian adolescents.

Pediatricians administered the PHQ-9 to 233 adolescent students aged 14-18 years, along with the Beck Depression Inventory. Our psychologist clinically diagnosed depression based on an International Classification of Diseases, 10th Revision, interview of participants. One month later, the PHQ-9 was readministered among students. We conducted appropriate analyses for validity and diagnostic accuracy.

A total of 31 students (13.3%) had a form of depression on psychiatric interview. A PHQ-9 score of ≥5 was ideal for screening (sensitivity, 87.1%; specificity, 79.7%). In addition to good content validity, PHQ-9 had good 1-month test-retest reliability (r = .875) and internal consistency (Cronbach's α = .835). There was high convergent validity with the Beck Depression Inventory (r = .76; p = .001). The concordance rate between the PHQ-9 threshold score of ≥10 and the International Classification of Diseases, 10th Revision based diagnosis was good (Cohen's κ = .62). The area under the receiver operating characteristic curve for PHQ-9 was .939.

The PHQ-9 is a psychometrically sound screening tool for use by pediatricians in a primary care setting in India. Because it is a short, simple, easy to administer questionnaire, the PHQ-9 has tremendous potential in helping to tackle the growing problem of depression among adolescents in developing countries.