Usefulness of the Patient Health Questionnaire-2 in Screening for Depression

ABSTRACT

BACKGROUND: While various screening tools are available for depression, they are not feasible in clinical practice because of their excessive number of questions. The Patient Health Questionnaire-2 (PHQ-2) consists of two questions gauging the frequency of depressed mood and anhedonia over the past two weeks. This study aimed to assess the usefulness of the PHQ-2 as a brief screening tool for depression.METHODS: This study used Korean National Health and Nutrition Examination Survey data from 2014, and the study population consisted of 4,946 individuals. We analyzed the validity of the PHQ-2 compared with ‘depression by PHQ-9,’ and obtained the optimal cut point for screening depression. The agreement between PHQ-2 and depression by PHQ-9 and the agreement between PHQ-2 and ‘currently diagnosed as depression’ were analyzed using Cohen's kappa. The correlation between EuroQol-5D (EQ-5D) index scores and PHQ-2 scores was analyzed using Student's t-test.RESULTS: Using ‘depression by PHQ-9’ as the criterion standard, PHQ-2 scores ≥2 had a sensitivity of 89% and a specificity of 87%, and a receiver operating characteristic analysis identified PHQ-2≥2 as the optimal cut point for screening. The agreement between PHQ-2 and depression by PHQ-9 was 0.430 when PHQ-2 ≥2 was used as a cut point. The agreement between PHQ-2 and ‘depression by questionnaire’ was poor. The EQ-5D index score of the depressive group was significantly lower than that of the normal group.CONCLUSION: The PHQ-2 is an effective measure for screening depression and is expected to be useful in busy clinical settings.