The association between traumatic brain injury and ADHD in a Canadian adult sample.

Objective: This study describes the association between lifetime traumatic brain injury (TBI) and attention deficit and hyperactivity disorder (ADHD) among Canadian adults.

Method: A cross-sectional sample of 3993 Ontario adults aged 18 or older were surveyed by Computer Assisted Telephone Interviewing (CATI) throughout 2011 and 2012 as part of the CAMH Monitor, a rolling survey assessing the health, mental health and substance use of Ontario adults. TBI was defined as trauma to the head that resulted in loss of consciousness for at least five minutes or overnight hospitalization. ADHD was measured by the 6-item ASRS screener for adult ADHD, and self-reported history of diagnosed ADHD.

Results: Among adults with a history of TBI, 6.6% (95% CI: 4.7, 9.4) screened ADHD positive, and 5.9% (95% CI: 3.6, 9.5) reported having been diagnosed with ADHD in their lifetime. Adults with lifetime TBI had significantly greater odds of scoring positive on the ADHD/ASRS screen (OR = 2.49, 95% CI: 1.54, 4.04), and of reporting a history of diagnosed ADHD (OR = 2.64, 95% CI: 1.40, 4.98) than without TBI, when holding values of sex, age, and education constant.

Conclusion: Significant positive associations between lifetime TBI and both current and past ADHD were observed among adults in this population. More research to understand these associations, and their significance for the etiology and management of TBI and ADHD, is needed.