ADHD News & Research

ADHD May Be Linked to Obesity in Girls

New research suggests that girls with ADHD are more likely to be obese than their non-ADHD peers.

February 10, 2016

Girls with ADHD may be more prone to obesity in childhood and early adulthood, a new study finds. This may be due to the shared brain mechanisms between ADHD and the development of eating disorders.

The study, conducted by the Mayo Clinic, followed 1000 patients born between 1976 and 1982, 336 of whom had been formally diagnosed with ADHD. Researchers measured rates of obesity at the time of diagnosis and at several follow-up intervals, ending in late August 2010.

The results showed that girls with ADHD were significantly more likely to be obese than their non-ADHD peers, both at the age at diagnosis and at each follow-up interval until age 20. Even girls with ADHD who weren’t obese at the time of diagnosis were 1.56 times more likely to be obese at age 20 than their non-ADHD counterparts. Overall, a higher proportion of ADHD females were obese after age 20 than non-ADHD females – 41.6 percent and 19.6 percent, respectively.

“There are a couple of biological mechanisms that underlie both obesity and ADHD,” said Dr. Seema Kumar, a pediatrician and one of the lead researchers on the study. Biological abnormalities in the brain related to dopamine have been found in both patients with ADHD and those with eating disorders. This may explain for both the prevalence of obesity and the high rates of eating disorders in adults and children with ADHD, said Kumar.

“Girls with ADHD may not be able to control their eating and may end up overeating,” she added. “Because kids with ADHD don’t have impulse control, it may also play a role in this.”

No similar association was seen in male patients, which Kumar thinks may be attributed to ADHD males’ more hyperactive tendencies, which could help them burn calories more effectively. “It is possible that there are differences in eating patterns with boys with ADHD or differences in the types of ADHD girls have,” she said.

About 65 percent of the patients were treated with stimulant medications at some point during the study. Researchers found no difference in obesity rates in the stimulant-treated group, though they did note an overall higher BMI (body mass index) in the group who had started stimulant medications the earliest. “These findings suggest that longer follow-up in children and adults who use stimulants is warranted,” said the researchers.

The study was conducted in Rochester, Minnesota, a community of primarily white, middle-class residents. Drawing larger conclusions to reflect more diverse communities may be challenging, researchers say. Other studies with similar premises had varying results, indicating that further research is needed before any causal conclusions can be drawn.