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

Abstract

Abstract Background 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. Methods 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. Results 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 < 0.01), and the Pearson’s correlation coefficient between each item and the total score was at the range of 0.608 ~ 0.773. Taking the results of MINI as the gold standard, the area under the receiver operating characteristic (ROC) curve of the PHQ-9 results for all the subjects (n = 277) was 0.898 (95% confidence interval (CI): 0.859 ~ 0.937, P < 0.01). When the cut-off score was equal to 5, the values of sensitivity, specificity, and the Youden’s index were 91.2, 76.6%, and 0.678, respectively. Multivariate logistic regression analysis showed that the influence of unemployment on the occurrence of depression was statistically significant (P = 0.027, OR = 3.080, 95%CI: 1.133 ~ 8.374). Conclusions The application of PHQ-9 for screening of depression among Chinese patients with neurological disorders showed a good reliability and validity.