Risk and outcomes for traumatic brain injury in patients with mental disorders

Objective: To investigate the risk of traumatic brain injury (TBI) and post-injury mortality in patients with mental disorders. Background: Patients with mental disorders are at higher risk of injuries. However, the association between mental disorders and TBI is still not understood. We conducted case-control studies to investigate whether people with pre-existing mental disorders are at higher risk of TBI and post-injury mortality. Methods: Using reimbursement claims, we analysed 16 635 patients with TBI and 66 540 controls with adjustment of covariates to study the association of mental disorders and TBI. A nested case-control study was also conducted to analyse contributory factors for post-injury mortality. Results: People with mental disorders were at increased risk of TBI (odds ratio (OR) 1.94, 95% confidence interval (CI) 1.86 to 2.02). Men, older age, living in highly urbanised areas and patients on low income had a higher risk of TBI and post-injury mortality. Psychiatric medication intensity and frequency of psychiatric visits was significantly correlated with TBI in a severity dependent relationship (p for trend <0.0001). Patients receiving advanced psychiatric healthcare had an increased risk of TBI (OR 2.98, 95% CI 2.67 to 3.33) and post-injury mortality (OR 1.92, 95% CI 1.34 to 2.77). A history of receiving psychiatric related outpatient care (OR 1.77, 95% CI 1.70 to 1.85), hospitalisation (OR 3.21, 95% CI 2.79 to 3.70) or emergency visits (OR 3.53, 95% CI 3.15 to 3.94) were highly associated with subsequent TBI. Conclusions: Patients with mental disorders have an increased risk of TBI. Intensity of psychiatric medication is associated with increased post-injury mortality. Special attention to prevent TBI among this disabled population is mandatory.