A systematic review of the literature and a meta-analysis investigating the relationship between mild traumatic brain injury (mTBI) and ADHD has been completed. The study indicates that mTBI is cerebral concussion and that there has been increasing interest from the coverage in the lay press re: the effects of mTBI in professional sports.

The authors hypothesize that individuals with ADHD commonly have a history of being risk-takers and have higher accident rates, which may predispose them to mTBI. Conversely, it has been hypothesized that mTBI could create a secondary ADHD-like condition.

The authors used reasonable inclusion criteria re: the studies included in the analyses (including being original research which examined ADHD and mTBI, used diagnostic criteria for ADHD and differentiated ADHD from learning disorders and mTBI from other types of TBI). They found five articles which met entry criteria for the meta-analysis; most, but not all, of the trials involved children.

They then examined the relative risk for one disorder being associated with the other disorder, based upon the temporal sequence of disorder onset. The authors found that there was no increased risk for TBI if ADHD occurred first.
However, if mTBI occurred first or if the temporal sequence was unclear there was about a two times elevated risk for ADHD. The overall finding of increased relative risks of ADHD and mTBI is important and highlights the need for clinicians to screen for the potential of these co-occurring disorders.
 

Reference:
J Atten Disord. 2014 Oct;18(7):576-84. doi: 10.1177/1087054714543371. Epub 2014 Jul 21. Mild traumatic brain injury and ADHD: a systematic review of the literature and meta-analysis. Adeyemo BO1, Biederman J2, Zafonte R1, Kagan E3, Spencer TJ3, Uchida M3, Kenworthy T3, Spencer AE3, Faraone SV4.