New study finds significant association between ADHD and TBI

A new study has found a "significant association" between adults who have suffered a traumatic brain injury at some point in their lives and who also have attention deficit hyperactive disorder.

The study, published today in the Journal of Psychiatric Research, supports research that found a similar association in children, said Dr. Gabriela Ilie, lead author of the study and a post-doctoral fellow at St. Michael's Hospital.

The data used in the adult study was collected by the Centre for Addiction and Mental Health's Monitor, a continuous, cross-sectional telephone survey of almost 4,000 Ontario residents age 18 and older. Traumatic brain injury was described as any injury to the head that resulted in loss of consciousness for at least five minutes or overnight hospitalization. ADHD was measured by self-reported history of an ADHD diagnosis or the Adult ADHD Self-Report Scale known as the ASRS.

Among adults with a history of TBI, 5.9 per cent reported having been diagnosed with ADHD in their lifetime and another 6.6 per cent screened positive for ADHD when the self-report scale was conducted during the phone survey.

Recent clinical studies have suggested a relationship between ADHD and TBI that were experienced in childhood.

"This is not be surprising because some of the most persistent consequences of TBI include ADHD-like symptoms, such as memory and attention impairment, deficits in executive functions such as planning and organization, processing consonants and vowels and impulsive behaviour," Dr. Ilie said.

Other studies have suggested that TBI may lead to psycho-neurological changes that facilitate ADHD or ADHD may increase the probability that a person may fall or have another accident that will result in a TBI.

"Therefore it may be useful to assess TBI history during screening and assessment of ADHD in the adult population," Dr. Ilie said.

Dr. Robert Mann, senior scientist at CAMH and co-principal investigator said this latest study extends previous findings from the research team about the association between TBI and mental health and addiction issues.

"These new data suggest a significant association between ADHD and TBI," Dr. Mann said. "We see that adults with TBI are more than twice as likely than those without to report symptoms of ADHD."

Traumatic brain injuries are increasing in developed countries. The World Health Organization has predicted that by 2020 TBI will become the third largest contributor of disease and disability in the world, following heart disease and depressions.

Injuries from team sports such as hockey and football have been identified as the main source of TBI among youth, while falls and motor vehicle collisions are the main causes among adults.