Patient Health Questionnaire-9 to Screen for Depression in Outpatients With Multiple Sclerosis

Abstract

Depression is common in multiple sclerosis (MS), with a reported lifetime prevalence of 25–50% and a median point prevalence of 14%. Identification and validation of brief screening tools is essential. The objective of this study was to determine whether the self-administered Patient Health Questionnaire-9 (PHQ-9) is a potentially useful screening tool for depression in an MS clinic population. The PHQ-9 is an increasingly used clinical tool that is brief and specifically queries the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders IV: Text Revision (DSM-IVTR) depression criteria, making it easier for the clinician to diagnose depressive disorders. It has been validated in multiple medical and neurological populations. A total of 248 patients were given the PHQ-9 in the clinic waiting room, and 225 (mean age 43 years, 69% women) provided full responses. Rates of PHQ-9 depression are reported based on two scoring methods. With syndrome-based PHQ-9 scoring, 26 patients (12%) met criteria for either major depression (n = 15, 7%) or subthreshold major depression (n = 11, 5%). With a cut score of ≥10, 19% met criteria for significant depression. Both results are comparable to reported prevalence rates of depression in the MS literature. Twenty patients meeting syndromal depression criteria on the PHQ-9 were available for formal psychiatric evaluation, and all were diagnosed with a depressive disorder. Depressive symptom profiles revealed a low frequency of frank depressed mood and a preponderance of somatic symptoms, particularly fatigue and sleep disturbance. These preliminary results suggest that the PHQ-9 may be a useful tool in screening for depression in outpatients with MS. A formal validation study is indicated.