The validity and reliability of the PHQ-9 on screening of depression in neurology: a cross sectional study

This study aimed to explore the validity and reliability of the Patient Health Questionnaire-9 (PHQ-9) on screening of depression among patients with neurological disorders, and to explore factors influencing such patients. In this study, 277 subjects who were admitted to the department of neurology of our hospital due to different neurological disorders completed the PHQ-9 questionnaire. The Mini-International Neuropsychiatric Interview (MINI) and Hamilton Rating Scale for Depression (HAMD) were employed to evaluate the depressive symptoms of patients who completed the PHQ-9 questionnaire. The internal consistency, criterion validity, structural validity, and optimal cut-off values of PHQ-9 were evaluated, and the consistency assessment was conducted between the depression severity as assessed by PHQ-9, HAMD and MINI. Logistic regression analysis was used to calculate the risk factors of depression. The Cronbach's α coefficient of the PHQ-9 was 0.839. The Pearson's correlation coefficient among the 9 items of the PHQ-9 scale was 0.160 ~ 0.578 (P