March 21, 2018
Traumatic brain injuries — or TBIs — affect as many as one million children each year in the U.S. Previous research has found that children who experience TBIs are more likely to develop ADHD in the years immediately following the injury; now, a small new study1 finds that the risk of developing ADHD remains elevated for nearly 10 years for this population, particularly if the injury is severe or if the child’s family is dysfunctional.
The study, published Monday in JAMA Pediatrics, followed 187 Ohio children — none of whom had been diagnosed with ADHD prior to the study — who had been hospitalized from January 2003 to June 2008. Eighty-one of the children had been hospitalized for TBIs ranging from mild to severe; the other 106 were hospitalized for broken bones, and served as a control group. For approximately 7 years following their hospitalization, the subjects were assessed for signs of ADHD at regular intervals.
Children in the TBI group were significantly more likely than those in the control group to develop attention-related symptoms later on, the researchers found. On the whole, children with TBI — mild, moderate, or severe — were twice as likely as children in the control group to develop ADHD at some point later on. The children with severe TBI were almost 4 times as likely.
Most ADHD symptoms appeared within 18 months of the injury, particularly if the injury was severe. However, for a small group of children with TBI, ADHD symptoms didn’t appear until several years later — in some cases, as much as 7 years after the injury occurred. Most of these children had undergone mild or moderate injuries, indicating to the researchers that the severity of the injury is positively correlated to the speed with which ADHD symptoms appear.
“While previous studies suggest kids with a history of traumatic brain injuries are at risk for developing attention problems, they only followed children 2 to 3 years after injury,” said lead author Megan Narad, Ph.D., in an interview with MedPage Today. “Our study is unique in that we followed children 7 to 10 years after their injury and demonstrated that some kids develop attention problems many years [later].”
Researchers also measured parental education levels and family dysfunction, finding that a parent’s response to their child’s injury may also impact a child’s likelihood of later developing ADHD. Children with TBIs whose families showed high levels of dysfunction — regardless of the severity of the brain injury — were slightly more likely to develop ADHD afterward, the researchers found.
Since the study relied mainly on parental reports, it may have missed the existence of mild ADHD symptoms before the TBI occurred, said Robert Asarnow, Ph.D., of the University of California, Los Angeles, who was not involved with the study. Still, the link between family dynamics, TBIs, and ADHD symptoms should be noted, he said — particularly by clinicians responsible for a child’s post-TBI treatment.
“Having a child incur significant brain injury is a traumatic event for a family,” he said to MedPage Today. “And if that child goes on to develop ADHD, [he or she] can be difficult to manage. If the family wasn’t getting along well before the injury, things can get worse; it works both ways.”
1 Narad, Megan E., et al. “Secondary Attention-Deficit/Hyperactivity Disorder in Children and Adolescents 5 to 10 Years After Traumatic Brain Injury.” JAMA Pediatrics, 19 Mar. 2018, doi:10.1001/jamapediatrics.2017.5746.