PHQ-9 Valid as Depression Screening Tool for Patients With Neurological Disorders

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In a cross-sectional study, researchers evaluated the validity and reliability of the PHQ-9 for patients with neurological disorders to screen for depression, and explore other factors that influence this patient population.

Patient Health Questionnaire-9 (PHQ-9) is a reliable and valid screening for depression among patients of Chinese ethnicity with neurological disorders, according to a study published in BMC Psychiatry.

Depression, ranked as the third cause of burden of disease worldwide in 2008, imposes serious health and economic liabilities on society, and is prevalent among patients dealing with various chronic conditions. Identifying severe depression cases that require advanced care is a challenge for clinicians and nonpsychiatric physicians. Screening tools such as interviews and rating scales are often utilized by health care systems but are limited by resources, number of trained professionals, and diagnostic value.

The objective of the current study was to evaluate the validity and reliability of the PHQ-9 for patients with neurological disorders to screen for depression, and explore other factors influencing such patients.

Researchers conducted a cross-sectional study from January 2016 to June 2016 and included 277 participants, 181 (65.3%) male, equal to or older than 18 years of age (mean age 60.56±15.53 years), and absent of a significant cognitive impairment, admitted to the department of neurology at the Peking University Third Hospital, Beijing, China, who then completed the PHQ-9. The Mini-International Neuropsychiatric Interview (MINI) and Hamilton Rating Scale for Depression (HAMD) were utilized for comparison in consistency with the PHQ-9 to evaluate depressive symptoms for internal consistency, criterion validity, structural validity, and optimal cut-off values.

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 <.01), and the Pearson’s correlation coefficient between each item and the total score was 0.608-0.773. Compared to MINI, the area under the receiver operating characteristic curve of the PHQ-9 results for all the subjects (n=277) was 0.898 (95% CI: 0.859-0.937; P <.01). Multivariate logistic regression analysis showed that the influence of unemployment on the occurrence of depression was statistically significant (P =.027, OR=3.080, 95% CI: 1.133-8.374).

Researchers stated, “the results showed that the prevalence of depression was 24.5%, which was similar to outpatients in different clinical specialties, but significantly higher than outpatients in healthy controls.”

Study limitations included participants from only one hospital, no retesting of reliability, and the effects of various neurological diseases on depression were not analyzed. Used with different populations, the PHQ-9 screening cut-off value changes, so the corresponding evaluation of the severity of depression may also change.

“The application of PHQ-9 for screening of depression among Chinese patients with neurological disorders showed a good reliability and validity,” the researchers concluded.


Sun Y, Kong Z, Song Y, Liu J, Wang X. The validity and reliability of the PHQ-9 on screening of depression in neurology: a cross sectional study. BMC Psychiatry. Published online February 9, 2022. doi:10.1186/s12888-021-03661-w