Study finds differences in brain structure between boys and girls with binge eating disorder

Study finds differences in brain structure between boys and girls with binge eating disorder

In conducting the first known comparison of the brains of boys and girls with binge eating disorder, a team of researchers from the Keck School of Medicine of USC found significant differences in brain structure between the sexes. The research results were recently published in Psychological Medicine.

The study, which builds on previous work suggesting that binge eating disorder is hardwired into the brain from an early age, is an important first step toward understanding the neurobiology of binge eating disorder and how it differs between the sexes. It also provides crucial evidence that men who have been excluded from eating disorder research in the past need to be included in future efforts to understand the origins of eating disorders.

“Men have been excluded from eating disorder research for decades,” said Stuart Murray, DClinPsych, PhD, Della Martin Associate Professor of Psychiatry and Behavioral Sciences at the Keck School of Medicine of USC, noting that the exclusion was perpetuated by the belief that it was unusual for men to have eating disorders. “Due to the exclusion of boys and men, we have developed treatments from studies of women only, which we then apply to boys and men and hope they work with the same effectiveness.”

However, in recent years it has become increasingly clear that some eating disorders are actually almost as common among men and boys as they are among women and girls. At the same time, research has found increasing evidence that eating disorders are brain diseases and not the result of social pressure or a lack of willpower, which Murray says are common misconceptions that have been debunked.

Same disease, different brain structure

Using data from the Adolescent Brain Cognitive Development Study, the largest study in the United States to assess brain development, researchers identified 38 boys and 33 girls diagnosed with binge eating disorder among the study's 11,875 participants. Among children, boys make up about 57% of those with binge eating disorder. This number changes in adults, with adult men accounting for approximately 43% of those with binge eating disorder.

The research team was able to assess gray matter density in the brains of the nine- and 10-year-olds in the study using voxel-based morphometry, a neuroimaging technique that allows researchers to examine differences in structural brain anatomy throughout the brain. It showed that girls with binge eating disorder had increased gray matter density in several parts of the brain known to be associated with impulse control and binge eating disorder symptoms, compared to a control group of 74 children matched for age, body mass index, and developmental maturity. However, boys with binge eating disorder did not have increased gray matter density in these areas. This increased gray matter density in girls with binge eating disorder suggests that a crucial brain maturation process – synaptic pruning – may be uniquely altered or delayed in these girls.

“This study clearly suggests that any neurobiological hypothesis of binge eating disorder must be stratified by gender.”

Stuart Murray, DClinPsych, PhD, Della Martin Associate Professor of Psychiatry and Behavioral Sciences, Keck School of Medicine of USC

Inclusion of men crucial for future treatments

Likewise, the fact that boys and girls with binge eating disorder, the most common type of eating disorder, have different brain structures suggests that men may need different types of treatment than women.

Murray added that new treatments for binge eating disorder are on the horizon and include transcranial magnetic stimulation and direct current stimulation, both of which directly target the brain. As with previous research on eating disorders, only female subjects have been included in the research.

“The differences in brain structure between boys and girls with binge eating disorder mean that any treatments targeting the brain need to be tested in both men and women,” Murray said. “Otherwise we would be targeting parts of the brain in men that are not necessarily abnormal.”

Next, Murray and his team will test whether the brains of men and women with binge eating disorder not only have different structures but also function differently.

Source:

Keck School of Medicine of USC

Reference:

Murray, S.B., et al. (2022) Sex differences in regional gray matter density in prepubertal binge eating disorder: a voxel-based morphometry study. Psychological medicine. doi.org/10.1017/S0033291722003269.

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