Abstract
To assess the reliability, construct validity, and screening accuracy of the Patient Health Questionnaire-2 (PHQ-2) and the combined PHQ-2/PHQ-9 to detect major depressive disorder (MDD) in persons with traumatic brain injury (TBI). We were especially interested in comparing the optimal PHQ-2 cutoff in this sample of people with TBI to the generic cutoff of three or higher that has been adopted by the Department of Veterans Affairs (VA) and the Centers for Medicare and Medicaid (CMS).
Screening validity study relative to structured diagnostic assessment
Level I trauma center
Participants were 135 adults within one year of sustaining complicated mild, moderate, or severe TBI.
Not applicable
PHQ-2 and PHQ-9 depression scales, Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (SCID).
The optimal cutoff for the PHQ-2 alone is a score of two or more which results in a sensitivity of.86 and a specificity of.83 relative to a diagnosis of MDD. When the PHQ-2 and PHQ-9 are combined in a two-step process, the optimal cutoffs to identify MDD are one or more on the PHQ-2 and a total of five or more of the nine PHQ-9 symptoms endorsed at least several days in the past two weeks. This resulted in a sensitivity of.93 and a specificity of.89. In terms of clinical efficiency, only 53.6% of patients needed to be administered the entire PHQ-9.
This study validates the use of the PHQ-2 and especially the use of a two-step PHQ-2/PHQ-9 to identify MDD in persons with TBI. The ideal PHQ-2 and PHQ-9 cutoff scores identified in this study are at variance with the generic cutoffs that have been adopted by the VA and CMS. Results suggest those generic screening parameters may fail to detect a large fraction of people with TBI with comorbid MDD. Larger, multi-center validity studies are needed to identify the best methods for depression screening in people with TBI and to ensure those methods are adopted widely as the standard of care. Regardless of the screening approach used, individuals who screen positive on the PHQ-2/PHQ-9 should be followed up with a clinical diagnostic assessment and encouraged to engage in evidence-based treatment, if indicated.