Structural brain differences in recovering and weight-recovered adult outpatient women with anorexia nervosa

Background: Anorexia nervosa is a complex psychiatric illness that includes severe low body weight with cognitive distortions and altered eating behaviors. Brain structures, including cortical thicknesses in many regions, are reduced in underweight patients who are acutely ill with anorexia nervosa. However, few studies have examined adult outpatients in the process of recovering from anorexia nervosa. Evaluating neurobiological problems at different physiological stages of anorexia nervosa may facilitate our understanding of the recovery process. Methods: Magnetic resonance imaging (MRI) images from 37 partially weight-restored women with anorexia nervosa (pwAN), 32 women with a history of anorexia nervosa maintaining weight restoration (wrAN), and 41 healthy control women were analyzed using FreeSurfer. Group differences in brain structure, including cortical thickness, areas, and volumes, were compared using a series of factorial f-tests, including age as a covariate, and correcting for multiple comparisons with the False Discovery Rate method. Results: The pwAN and wrAN cohorts differed from each other in body mass index, eating disorder symptoms, and social problem solving orientations, but not depression or self-esteem. Relative to the HC cohort, eight cortical thicknesses were thinner for the pwAN cohort; these regions were predominately right-sided and in the cingulate and frontal lobe. One of these regions, the right pars orbitalis, was also thinner for the wrAN cohort. One region, the right parahippocampal gyrus, was thicker in the pwAN cohort. One volume, the right cerebellar white matter, was reduced in the pwAN cohort. There were no differences in global white matter, gray matter, or subcortical volumes across the cohorts. Conclusions: Many regional structural differences were observed in the pwAN cohort with minimal differences in the wrAN cohort. These data support a treatment focus on achieving and sustaining full weight restoration to mitigate possible neurobiological sequela of AN. In addition, the regions showing cortical thinning are similar to structural changes reported elsewhere for suicide attempts, anxiety disorders, and autistic spectrum disorder. Understanding how brain structure and function are related to clinical symptoms expressed during the course of recovering from AN is needed. Anorexia nervosa is a life-threatening mental illness defined in part by an inability to maintain a body weight in the normal range. Malnutrition and low weight are factors typically present in the anorexia nervosa and can affect brain structure. We conducted a detailed analysis of brain structure using Freesurfer, focusing on regional cortical thicknesses, areas, and volumes, in adult outpatient women with anorexia nervosa. The study included both a partially weight-restored cohort with anorexia nervosa, a cohort sustaining a healthy body weight with history of anorexia nervosa, and a healthy comparison cohort. Reduced cortical thicknesses were observed in eight regions, primarily in the frontal lobe and cingulate for the cohort recently with anorexia nervosa but only one frontal region in the weight-maintained cohort. These data emphasize the importance of sustained weight-restoration for adult women with anorexia nervosa. Further, the impacted neural regions have been associated with impulsivity, attention, self-regulation, and social interactions in other clinical cohorts, suggesting that these neuropsychological processes may warrant study in patients recovering from anorexia nervosa. Future work should consider whether these factors have clinical relevance in the outpatient treatment of adults with anorexia nervosa.