Atypical anorexia nervosa is not related to brain structural changes in newly diagnosed adolescent patients

Abstract

Objective: Patients with atypical anorexia nervosa (AN) have many features overlapping with AN in terms of genetic risk, age of onset, psychopathology and prognosis of outcome, although the weight loss may not be a core factor. While brain structural alterations have been reported in AN, there are currently no data regarding atypical AN patients.Method: We investigated brain structure through a voxel-based morphometry analysis in 22 adolescent females newly-diagnosed with atypical AN, and 38 age-and sex-matched healthy controls (HC). ED-related psychopathology, impulsiveness and obsessive-compulsive traits were assessed with the Eating Disorder Examination Questionnaire (EDE-Q), Barratt Impulsiveness Scale (BIS-11) and Obsessive-compulsive Inventory Revised (OCI-R), respectively. Body mass index (BMI) was also calculated.Results: Patients and HC differed significantly on BMI (p < .002), EDE-Q total score (p < .000) and OCI-R total score (p < .000). No differences could be detected in grey matter (GM) regional volume between groups.Discussion: The ED-related cognitions in atypical AN patients would suggest that atypical AN and AN could be part of the same spectrum of restrictive-ED. However, contrary to previous reports in AN, our atypical AN patients did not show any GM volume reduction. The different degree of weight loss might play a role in determining such discrepancy. Alternatively, the preservation of GM volume might indeed differentiate atypical AN from AN. K E Y W O R D Sadolescent, anorexia, eating disorders, imaging, MRI, OSFED, VBM

Preserved white matter microstructure in adolescent patients with atypical anorexia nervosa

“…However our current imaging findings, coupled with our previous VBM study reporting preserved grey matter volumes in atypical AN (Olivo et al, 2018), suggest that the brain structural correlates of atypical AN may differ from full syndrome AN. In fact, in adolescents with full syndrome AN, WM microstructural alterations can be seen in the brain even at early stages (Gaudio et al, 2017;Travis et al, 2015), so whether our previous findings might have been driven by the inclusion of patients with full syndrome AN is an open question.…”

“…Ten patients and 18 controls of our current sample were also included in our previous DTI study on restrictive EDs (Olivo et al, 2017). Sixteen patients and 22 controls of our current sample were also included on our previous voxel-based morphometry (VBM) study on atypical AN (Olivo et al, 2018).…”

Editorial to the virtual issue highlighting neuroscience based research in eating disorders to mark the 49th Society for Neuroscience Annual Meeting

“…Atypical anorexia nervosa is defined as anorexia nervosa that does not meet full diagnostic criteria, typically those individuals are not below a certain weight threshold, such as the 5th percentile for age adjusted BMI. Two studies by Olivo et al found normal gray and white matter in adolescents with atypical anorexia nervosa, further supporting the hypothesis that body weight is directly related to brain structure, although the mechanism is not yet well understood (Frintrop et al, 2017;Olivo et al, 2018;Olivo et al, 2019).…”

Tackling mixed messages: Practitioner reflections on working with adolescents with atypical anorexia and their families

“…Relative to anorexia nervosa (AN), bulimia nervosa, and binge eating disorder, a dearth of research literature has focused on atypical AN in children and adolescents. This is despite the fact that emerging evidence points to conspicuous differences between this patient population and adolescents with AN (e.g., Hughes, Le Grange, Court, & Sawyer, 2017;Olivo et al, 2018). Atypical AN, which falls under the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5; American Psychiatric Association, 2013) diagnosis of Other Specified Food and Eating Disorders, occurs when an individual meets all criteria for AN, but despite significant weight loss, their current weight is within or above population norms for their sex and age.…”