Risk of traumatic brain injury among patients with ADHD and their unaffected siblings.

BACKGROUND: As the relationship between attention deficit hyperactivity disorder (ADHD) and traumatic brain injury (TBI) is gaining increasing attention, the TBI risk in patients with ADHD, unaffected siblings of ADHD probands, and non-ADHD controls remains unclear.

METHODS: Overall, 18,645 patients with ADHD, 18,880 unaffected siblings of ADHD probands, and 188,800 age-/sex-matched controls were followed up from enrollment to the end of 2011. The cases of TBI and TBI requiring hospitalization were identified during follow-up.

RESULTS: Patients with ADHD (hazard ratio [HR]: 1.57) and unaffected siblings (HR: 1.20) had an increased risk of any TBI compared with non-ADHD controls. Surprisingly, the likelihood of developing TBI requiring hospitalization during follow-up was higher in the unaffected siblings group (HR: 1.21) than in the control group, whereas it was lower in the ADHD probands group (HR: 0.86).

CONCLUSIONS: Patients with ADHD and unaffected siblings of ADHD probands were more likely to develop any TBI during follow-up than controls. Unaffected siblings of patients with ADHD exhibited the highest risk of subsequent TBI requiring hospitalization compared with patients with ADHD and healthy controls. Therefore, TBI risk in patients with ADHD and their unaffected siblings would require further investigation.

IMPACT: ADHD diagnosis and ADHD trait are associated with risk of traumatic brain injury (TBI). Both patients with ADHD and their unaffected siblings were more likely to develop TBI during the follow-up compared with the control group. TBI requiring hospitalization occurred more in the sibling group than in the proband group. TBI risk should be closely monitored among unaffected siblings of patients with ADHD.