Psychiatric Disorders After Traumatic Brain Injury: A Nationwide Population-Based Cohort Study and the Effects of Rehabilitation Therapies.

OBJECTIVE: To investigate the risk of psychiatric disorders after traumatic brain injury (TBI), and to clarify whether the post-TBI rehabilitation was associated with a lower risk of developing psychiatric disorders. DESIGN: A register-based, retrospective cohort design. SETTING: Using data from the National Health Insurance Research Database of Taiwan, we established an exposed cohort with TBI and a nonexposed group without TBI matched by age and year of diagnosis between 2000 and 2015. PARTICIPANTS: This study included 231,894 patients with TBI and 695,682 patients without TBI (N=927,576). INTERVENTIONS: Rehabilitation therapies in TBI patients. MAIN OUTCOME MEASURES: A multivariable Cox proportional hazards regression model was used to compare the risk of developing psychiatric disorders. RESULTS: The incidence rate of psychiatric disorders was higher in the TBI group than the control group. Compared with the control group, the risk of psychiatric disorders in the TBI group was twofold (hazard ratio [HR]=2.072; 95% confidence interval [95% CI], 1.955-2.189; P<.001). Among the participants with TBI, 49,270 (21.25%) had received rehabilitation therapy and had a lower risk of psychiatric disorders (HR=0.691; 95% CI, 0.679-0.703; P<.001). In the subgroup analysis, the medium- to high-level intensity rehabilitation therapy was associated with lower risks of psychiatric disorder (HR=0.712 and 0.568, respectively), but there was no significant finding in the low-intensity group. CONCLUSIONS: We found that TBI was associated with a high risk for developing psychiatric disorders, and that the post-TBI rehabilitation significantly reduced the risk of psychiatric disorders in a dose-dependent manner.