Clinical Utility of the Patient Health Questionnaire-9 in the Assessment of Major Depression After Broad-Spectrum Traumatic Brain Injury.

OBJECTIVE: To determine the predictive validity of the Patient Health Questionnaire-9 (PHQ-9) when screening for symptoms of depression after traumatic brain injury.

DESIGN: Retrospective analysis of data collected as part of routine clinical outpatient care over a period of 30 months.

SETTING: Regional rehabilitation facility.

PARTICIPANTS: Persons (N=137) with mild to severe traumatic brain injury who were referred for neuropsychological evaluation within 1 to 12 months.

INTERVENTIONS: Not applicable.

MAIN OUTCOME MEASURES: PHQ-9 and Minnesota Multiphasic Personality Inventory-2-Restructured Form.

RESULTS: PHQ-9 scores ≥10 had a sensitivity of 91.7 and a specificity of 60.2 for predicting a diagnosis of major depression. Correlations between scores of PHQ-9 and Minnesota Multiphasic Personality Inventory-2-Restructured Form Demoralization (.64) and Low Positive Emotions (.48) scales ranged from large to medium. Premorbid outpatient psychiatric treatment was the most consistent predictor of PHQ-9 elevations as well as final diagnoses of major depression.

CONCLUSIONS: The PHQ-9 has adequate clinical utility as a screening instrument for depression in outpatients with traumatic brain injury. Elevations on this instrument cannot, however, be automatically attributed to neuropathology, especially not in the context of premorbid psychiatric dysfunction. Clinicians should conduct more thorough follow-up assessment in those with highly elevated PHQ-9 scores.