Olfactory function and alternation learning in eating disorders

Edmond and Lily Safra Children's Hospital, Chaim Sheba Medical Center, Tel Hashomer, Israel.
European neuropsychopharmacology: the journal of the European College of Neuropsychopharmacology (Impact Factor: 4.37). 07/2012; 22(9):615-24. DOI: 10.1016/j.euroneuro.2011.12.006
Source: PubMed


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.

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    • "not controlling for hyposmia and depression . The rest of the 13 studies ( Fedoroff et al . , 1995 ; Kopala et al . , 1995 ; Obrebowski et al . , 2000 ; Lombion - Pouthier et al . , 2006 ; Simchen et al . , 2006 ; Schreder et al . , 2008 ; Rapps et al . , 2010 ; Weiland et al . , 2011 ; Goldzak - Kunik et al . , 2012 ; Schecklmann et al . , 2012 ; Stein et al . , 2012 ; Dazzi et al . , 2013 ; Fernández - Aranda et al . , 2015 ) scored ( + ) because it is believed that they fulfilled at least some of the criteria where the conclusion is unlikely to change upon repetition . The findings of these studies are further explored in the following sections ."
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    ABSTRACT: The study provides a systematic review that explores the current literature on olfactory capacity in abnormal eating behavior. The objective is to present a basis for discussion on whether research in olfaction in eating disorders may offer additional insight with regard to the complex etiopathology of eating disorders (ED) and abnormal eating behaviors. Electronic databases (Medline, PsycINFO, PubMed, Science Direct, and Web of Science) were searched using the components in relation to olfaction and combining them with the components related to abnormal eating behavior. Out of 1352 articles, titles were first excluded by title (n = 64) and then by abstract and fulltext resulting in a final selection of 14 articles (820 patients and 385 control participants) for this review. The highest number of existing literature on olfaction in ED were carried out with AN patients (78.6%) followed by BN patients (35.7%) and obese individuals (14.3%). Most studies were only conducted on females. The general findings support that olfaction is altered in AN and in obesity and indicates toward there being little to no difference in olfactory capacity between BN patients and the general population. Due to the limited number of studies and heterogeneity this review stresses on the importance of more research on olfaction and abnormal eating behavior.
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