Comorbidity of pain and depression among persons with traumatic brain injury.

OBJECTIVE: To assess the prevalence of pain, depression, and comorbid pain and depression among a civilian sample of persons with traumatic brain injury (TBI). DESIGN: Longitudinal survey design with 1-year follow-up. SETTING: Inpatient rehabilitation and the community. PARTICIPANTS: Participants (N=158) admitted to inpatient rehabilitation after moderate to severe TBI. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Depression was assessed with the Patient Health Questionnaire-9 (PHQ-9); pain was assessed with a numerical rating scale from 0 (no pain) to 10 (worst pain). Participants who reported average pain ≥ 4 were classified as having pain, and participants with PHQ-9 scores ≥ 10 were classified as depressed. RESULTS: Both pain and depression were more prevalent at baseline assessment (pain: 70%; depression: 31%) than at year 1 (pain: 34%; depression: 22%). Comorbid pain and depression declined from 27% at baseline to 18% at year 1. Pain was significantly associated with depression at baseline (relative risk: 2.62, P=.003) and at year 1 (relative risk: 7.98, P<.001). CONCLUSIONS: Pain and depression are common and frequently co-occur in persons with TBI. Although their frequency declined over the first year after injury, the strength of their association increased. Assessment and treatment of both conditions simultaneously may lead to improved outcomes, both early after TBI and over time.