Incidence of New Neuropsychiatric Disorder Diagnoses following Traumatic Brain Injury

Background: Neuropsychiatric disturbances (NPDs) are common following traumatic brain injury (TBI) and associated with poor recovery. Prior estimates of NPD following TBI failed to account for preexisting NPDs or potential confounding. Methods: We estimated the risk of anxiety, posttraumatic stress disorder (PTSD), bipolar disorder, and alcohol and substance dependence disorder diagnoses associated with TBI using administrative claims data from a large insurer in the United States, 2008-2014. We calculated rates of new NPD diagnoses during the 12 months before and 24 months after TBI and estimated the risk of NPD following TBI using a difference-in-difference approach and adjusting for confounders. Results: Before the TBI occurred, rates of NPD diagnoses were more than double in the TBI cohort (n = 207 354) relative to the no-TBI cohort (n = 414 708). TBI was associated with an increased risk of anxiety (rate ratio [RtR] = 1.08; 95% confidence interval [CI], 1.05-1.12) and PTSD (RtR = 1.41; 95% CI, 1.24-1.60) diagnoses. Rates of alcohol (RtR = 0.32; 95% CI, 0.30-0.34) and substance use disorder (RtR = 0.57; 95% CI, 0.55-0.59) diagnoses decreased following TBI. Conclusions: In this large national study, rates of NPD were much higher among individuals with TBI than those in a non-TBI cohort, even before the TBI took place. TBI was associated with an increased risk of anxiety and PTSD diagnoses. Results from this study also suggest that individuals who sustain TBI have increased contact with the healthcare system during the months prior to injury, providing a window for intervention, especially for individuals diagnosed with alcohol dependence disorder.