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

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 a 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 similar to 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 similar to 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 (CD: 0.859 similar to 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 similar to 8.374). Conclusions: The application of PHQ-9 for screening of depression among Chinese patients with neurological disorders showed a good reliability and validity.

Automated summary

This study explored the validity and reliability of PHQ-9 for screening depression among patients with neurological disorders and identified factors influencing such patients. The results demonstrated good reliability and validity of PHQ-9 in the Chinese population. Unemployment was found to be a significant risk factor for depression in patients with neurological disorders.