Eating disorder behaviors linked to changes in brain reward processing

Eating disorder behaviors appeared to change brain reward processing, according to results of a cross-sectional imaging study published in JAMA Network Open.

Specifically, BMI modulated prediction error and food intake control circuitry in the brain, and alteration of this circuitry may reinforce eating disorder behaviors when paired with behavioral traits linked to overeating or undereating, researchers noted.

“Food restriction, episodic binge eating or purging vary across the diagnostic groups, whereas body dissatisfaction and drive for thinness are typically elevated across all eating disorders, as are anxious traits and sensitivity to salient stimuli,” Guido K. W. Frank, MD, of the department of psychiatry at the University of California, San Diego, and colleagues wrote. “Identifying how those behaviors are associated with particular biologic mechanisms could help create a better understanding of the underlying eating disorder pathophysiologic factors and development of specific treatments. To adopt a dimensional conceptualization of eating disorder specific behaviors and neurobiologic factors, we recruited individuals across the eating disorder spectrum and applied the prediction error construct from the National Institute of Mental Health Research Domain Criteria (RDoC) project.”

The investigators aimed to evaluate brain response during unexpected receipt or omission of a salient sweet stimulus in 317 women, of whom 197 had eating disorders and 120 served as healthy controls, and to determine whether this brain response was linked to the ventral striatal-hypothalamic circuitry, which has correlated with food intake control. Participants had a mean age of 23.8 years and mean BMI of 20.8. Further, they sought to determine whether associations existed between salient stimulus response and eating disorder related behaviors. To do so, they matched young adults across the eating disorder spectrum with healthy controls at a university brain imaging facility and eating disorder treatment program. They conducted a sucrose taste classic conditioning paradigm and noted that by violating learned associations between conditioned visual and unconditioned taste stimuli, participants’ dopamine-related prediction error was evoked. Further, the researchers evaluated hierarchical brain activation between brain regions related to food intake by studying dynamic effective connectivity during expected sweet taste receipt. Main outcomes and measures included prediction error brain reward response across insula and striatum; dynamic effective connectivity between hypothalamus and ventral striatum; and demographic and behavior variables and their associations with prediction error brain response and connectivity edge coefficients.

Results showed an elevated prediction error response among participants with anorexia nervosa. Among those with eating disorders, prediction error response was inversely associated with BMI, eating disorder inventory-3 binge eating tendency and trait anxiety. The researchers noted ventral striatal to hypothalamus directed connectivity was positively associated with ventral striatal prediction error in eating disorders and negatively associated with feeling out of control after eating.

“Temperamental traits are biologically oriented behaviors that affect eating disorder behaviors,” Frank and colleagues wrote. “Treatment modules that specifically target those behaviors may be a key element to promote behavior change and lasting recovery.”