The brains of girls and boys who have binge eating disorder show key differences, according to a new study.
That's an important finding, researchers say, because both genders struggle with eating disorders, yet treatments are mainly targeted at girls.
"Males have been excluded from research on eating disorders for decades," said Stuart Murray, an associate professor of psychiatry and behavioral sciences at the University of Southern California's Keck School of Medicine.
He noted that the exclusion stems from the belief that it was uncommon for males to have eating disorders.
"As a result of the exclusion of boys and men, we have developed treatments only from studying females, which we then apply to boys and men and hope they work with the same efficacy," Murray said in a school news release.
Some eating disorders are nearly as prevalent among men and boys as in women and girls. Evidence is mounting that eating disorders are diseases of the brain and not the result of social pressure or a lack of willpower, according to researchers.
This research team used data from a study of adolescent brain development that included more than 11,800 participants. Researchers identified 38 boys and 33 girls who had a diagnosis of binge eating disorder. In all kids, boys represent about 57% of those with binge eating disorder. Adult males represent about 43% of those with the disorder.
The study found significant differences in brain structure between boys and girls.
Researchers used a neuroimaging technique to examine the density of gray matter in the brains of the 9- and 10-year-old study participants. They compared what they found in those kids to a control group of 74 children who matched on age, developmental maturation and body mass index (BMI), an estimate of body fat based on height and weight.
Girls with binge eating disorder had elevated gray matter density in several parts of the brain that are known to be connected to impulse control and binge eating symptoms.
The boys with binge eating disorder did not have elevated gray matter density in these areas.
This suggests a crucial brain maturation process known as synaptic pruning may be uniquely altered or delayed in these girls, the researchers said.
"This study clearly suggests that any neurobiological hypothesis of binge eating disorder needs to be stratified by sex," Murray said.
The study builds on earlier work that suggested that binge eating disorder was wired in the brain from an early age.
While new treatments such as direct current stimulation targeted to the brain are close, only female subjects have been included in the research so far.
"The differences in brain structure between boys and girls with binge eating disorders means that any treatments targeting the brain must be tested on males as well as females," Murray said. "Otherwise, we would be targeting parts of the brain in males that aren't necessarily abnormal."
Researchers plan to test whether the brains of males and females, with their different structures, function differently.
They consider this work an important first step in understanding the neurobiology of binge eating disorder. They also noted that males must be included in future efforts to understand these issues.
Findings were recently published in Psychological Medicine.
The U.S. National Institute on Mental Health has more on eating disorders.
SOURCE: Keck School of Medicine of USC, news release, Nov. 9, 2022