PHQ-9 may offer effective depression screening in patients with neurological disorders

The Patient Health Questionnaire-9 appeared reliable and valid for depression screening among patients with neurological disorders, according to study results published in BMC Psychiatry.

“Regarding the use of the PHQ-9, there lies several problems, such as the cut-off value, the inconsistency of reliability and validity when used in neurology and the language expression, which may need to be adjusted,” Yajing Sun, of Peking University Institute of Mental Health in China, and colleagues wrote. “PHQ-9 needs to be further explored in patients with neurological disorders in order to improve its diagnostic value.”

Sun and colleagues sought to examine the effectiveness of the PHQ-9 for screening of depression in patients with neurological disorders, as well as to pinpoint factors that affect these patients. They analyzed PHQ-9 questionnaire responses from 277 patients admitted to a neurology department at Peking University and used the Mini-International Neuropsychiatric Interview (MINI) and Hamilton Rating Scale for Depression to assess depressive symptoms.

Researchers calculated reliability coefficients as measured by Cronbach’s alpha to determine reproducibility and consistency of the PHQ-9. They noted a Cronbach’s alpha coefficient of 0.839, as well as a Pearson’s correlation coefficient among the nine items of the PHQ-9 scale of 0.16 to 0.578 (P < .01). The Pearson’s correlation coefficient between each item and the total score ranged from 0.608 to 0.773. Sun and colleagues used the results of the MINI as the “gold standard” and reported an area under the receiver operating characteristic curve of the PHQ-9 results for all participants of 0.898 (P < .01). Further, they reported values of sensitivity, specificity and the Youden’s index score of 91.2, 76.6% and 0.678, respectively, when the cut-off score equaled five. Multivariate logistic regression revealed statistical significance for the impact of unemployment on depression occurrence (P = .027).

“Since depression can bring many adverse prognoses to patients, even lead to suicide, early identification of depression needs the attention of non-psychiatrists,” Sun and colleagues wrote. “Our study demonstrated good reliability and validity of the PHQ-9 by applying this questionnaire to screen depressed patients in a neurology department of general hospital. PHQ-9 is worth promoting and applying in the general hospital department of neurology.”