ADHD Onset Possible Years After Childhood Brain Injury

A new study shows that children who experience traumatic brain injuries (TBIs) are at greater risk of developing secondary attention-deficit/hyperactivity disorder (SADHD).

Megan E. Narad, PhD, Cincinnati Children’s Hospital Medical Center, Division of Physical Medicine and Rehabilitation, led a team of researchers who investigated the long-term effects of TBI as well as family dysfunction on the development of SADHD. Previous research about the impact of TBI on the development of SADHD only followed subjects for 2-3 years, potentially overlooking children who developed SADHD several years after experiencing TBI.

The researchers followed a cohort of 187 children, aged 3-7 years, who each had an overnight hospital stay for either traumatic brain injury (TBI) or, for the control group, orthopedic injury (OI). Parents completed assessments at baseline (0-3 months), 6 months, 12 months, 18 months, 3.4 years, and 6.8 years after injury. The parent questionnaire covered basic demographics, behavioral and mental health diagnoses, and treatment for behavioral or emotional symptoms. Patients’ family functioning and socioeconomic status were also collected.

As could be expected, researchers found that “61.9% of children with severe TBI (13 of 21) developed SADHD, whereas 15.1% of children with OI (16 of 106) developed SADHD by the start of middle school (approximately 7 years after injury).”

Most children with severe TBI who developed SADHD did so within the first 18 months after injury, however, a portion of those with complicated mild and moderate TBI reported new onset of SADHD at the final 2 assessments.

Lower maternal educational level and greater family dysfunction were significantly associated with elevated risk of SADHD among those with TBI. Within the OI group, minimal association with family dysfunction was observed, prompting researchers to call for further study of children with high levels of family dysfunction.

Although patients with severe TBI were at greatest risk of developing SADHD, children with less severe brain injuries were still twice as likely to display attention problems as compared with those in the OI control group.

“While previous studies have shown that kids with a history of TBI are at risk for developing attention problems, they only followed kids 2-3 years after injury,” Narad told MD Magazine. “Our study is unique in that we followed children 7-10 years after their injury and demonstrated that some kids develop attention problems many years after injury.”

“Of note, 8 of the 13 children (61.5%) with severe TBI who developed SADHD did so within the first year after their injury, whereas 3 of 6 children (50.0%) with moderate TBI and 7 of 13 (53.8%) with complicated mild TBI who developed SADHD did so later than the first year after injury,” researchers wrote.

Given these results, the researchers recommend a close monitoring of children with a history of brain injury even when it has been many years since the injury or in the case of a moderate injury. Narad added that following TBI, “when counseling patients and their families, it would be important to discuss the potential for development of attention problems… and it is important to monitor periodically for these risk factors.”

The study, “Secondary Attention-Deficit/Hyperactivity Disorder in Children and Adolescents 5 to 10 Years After Traumatic Brain Injury,” was published in the Journal of the American Medical Association.