Psychiatry AdvisorStructural Brain Differences Identified in Women with Bulimia Nervosa

🧠 Mental Health / Behavioral Sensitivity

Researchers conducted a multicenter case-control neuroimaging analysis using data from 17 cohorts participating in the ENIGMA Eating Disorders Working Group. The study included 786 women, comprising 369 participants with bulimia nervosa and 417 healthy controls. Using standardized MRI processing methods, investigators assessed cortical thickness, cortical surface area, and subcortical volumes to identify structural brain characteristics associated with bulimia nervosa diagnosis and symptom severity. Compared with controls, participants with bulimia nervosa demonstrated reductions in total cortical surface area and nucleus accumbens volume, with additional associations observed between binge-eating frequency and structural differences across multiple cortical regions. The cross-sectional design limits conclusions regarding causality or whether these findings represent causes, consequences, or correlates of illness.

Clinical Considerations

• Participants with bulimia nervosa demonstrated smaller total cortical surface area compared with healthy controls (d = -0.20).
• The largest surface-area differences were observed in the superior temporal gyrus (d = -0.26) and transverse temporal gyrus (d = -0.24).
• Participants with bulimia nervosa also demonstrated reduced nucleus accumbens volume (d = -0.20), a region frequently implicated in reward processing.
• Structural differences remained significant after adjustment for BMI, age-adjusted BMI, purging behavior, psychotropic medication use, illness duration, and depressive symptom severity.
• More frequent binge eating was associated with smaller surface area across regions involved in reward processing, cognitive control, interoception, and self-referential processing, including the insula, orbitofrontal cortex, cingulate cortex, and frontal regions.
• Exploratory analyses identified additional associations between driven exercise, dietary restriction, laxative or diuretic misuse, and structural differences in select brain regions.
• The study was cross-sectional, preventing determination of whether observed neuroanatomic differences precede illness onset or emerge during the course of disease.

Practice Applications

• Recognize that bulimia nervosa may be associated with measurable alterations in brain regions involved in reward, cognitive control, and interoceptive processing.
• Interpret these findings as supportive of neurobiological models of bulimia nervosa rather than evidence for clinical neuroimaging use in diagnosis.
• Avoid inferring causality, as the study design cannot determine whether structural differences contribute to illness risk or develop secondary to illness-related behaviors.
• Consider the findings hypothesis-generating and potentially informative for future research into disease mechanisms and treatment targets.
• Discuss neurobiological findings carefully with patients to reduce stigma while avoiding overstatement of current clinical applicability.