title: Olfactory function and alternation learning in eating disorders.
abstract: Orbitofrontal dysfunction is a prominent feature of obsessive compulsive disorder (OCD). In the present study we assessed orbitofrontal functioning in eating disorders (EDs) which share many features with OCD. For this purpose we studied female adolescent inpatients with anorexia nervosa restricting type (n=40), anorexia nervosa binge/purge type (n=23), a normal weight group including patients with either bulimia nervosa or eating disorder not otherwise specified-purging type (n=33), and 20 non-ED control females. Patients were assessed at admission, and when achieving weight restoration and symptom stabilization at discharge, for depression, non-ED, and ED-related OC symptoms. Orbitofrontal functioning was assessed with an alternation learning task, and with a battery assessing olfactory threshold and discrimination. Control females were assessed once. ED patients of all subtypes performed better on olfactory threshold and discrimination, but not on alternation learning, in comparison to healthy controls. More favorable orbitofrontal functioning was associated with greater ED-related obsessionality. No changes were found in olfactory threshold and discrimination between acutely-ill and symptomatically-stabilized patients. The improvement shown in alternation learning from admission to discharge was suggested to reflect a learning effect rather than being an actual change. Our findings suggest that the better orbitofrontal functioning of ED patients in comparison to healthy controls may represent a core feature of the ED that is independent of malnutrition and deranged eating behaviors, but is associated with ED-related obsessionality.
authors.affiliation: Edmond and Lily Safra Children's Hospital, Chaim Sheba Medical Center, Tel Hashomer, Israel.
authors.forename: Daniel
authors.initials: D
authors.lastname: Stein
authors.forename: Ruth
authors.initials: R
authors.lastname: Gross-Isseroff
authors.forename: Roni
authors.initials: R
authors.lastname: Besserglick
authors.forename: Amir
authors.initials: A
authors.lastname: Ziv
authors.forename: Gad
authors.initials: G
authors.lastname: Mayer
authors.forename: Amit
authors.initials: A
authors.lastname: Yaroslavsky
authors.forename: Anat
authors.initials: A
authors.lastname: Toledano
authors.forename: Hillary
authors.initials: H
authors.lastname: Voet
authors.forename: Abraham
authors.initials: A
authors.lastname: Weizman
authors.forename: Haggai
authors.initials: H
authors.lastname: Hermesh
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior / Q000502:physiology / Q000523:psychology; D003863:Depression / Q000150:complications / Q000503:physiopathology / Q000523:psychology; D004056:Differential Threshold / Q000502:physiology; D001068:Feeding and Eating Disorders / Q000503:physiopathology* / Q000523:psychology*; D005260:Female; D006801:Humans; D007361:Intelligence Tests / Q000706:statistics & numerical data; D007858:Learning / Q000502:physiology*; D009771:Obsessive-Compulsive Disorder / Q000150:complications / Q000503:physiopathology / Q000523:psychology; D055696:Olfactory Perception / Q000502:physiology*; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D013997:Time Factors