Cognitive functioning as an endophenotype of anorexia nervosa.A study in first-degree relatives unaffected by the disease

Abstract

The cognitive profile of patients with anorexia nervosa is characterized by difficultiesin central coherence and mental flexibility.Central coherence is defined by the ability tointegrate incoming information in its owncontext, and weakness in central coherence ischaracterized by poor overall processing andsuperior detail processing. Mental flexibility isdefined by the ability to change the course of athought or action according to the demands ofthe environment. Alterations in this cognitivedomain generate rigid and inflexible behavior.An open question in the literature is whetherthese cognitive characteristics are a transientstate derived from the disease or whetherthey are stable traits associated with anorexianervosa and endophenotypical features of thisdisease. The concept of endophenotype refersto the internal phenotype that is not clinicallyappreciable but can be observed indirectlythrough deficits that arise in the performanceof certain neuropsychological tests. In recentyears the search for endophenotypes has beenrenewed in the field of psychiatry as theywould constitute an important route for theunderstanding of the biological and geneticbases of mental illnesses, constituting markersthat allow a diagnosis before the onset of clinicalsymptomatology. For a cognitive markerto be considered an endophenotype it must meet a series of characteristics such as beingmeasurable, inherited, found in patients withand without active disease and in first-degreerelatives not affected by the disease. The aimof the present study was to assess whetherdifficulties in central coherence and mentalflexibility are shared by unaffected first-degreerelatives of patients with anorexia nervosa andthus constitute an endophenotypical feature ofthis disease.This is a cross-sectional, descriptive-comparativestudy in which 34 women participated:17 unaffected first-degree relatives ofpatients with anorexia nervosa (mothers andsisters) and 17 healthy controls matched byage and education. For the study of centralcoherence the copy of Rey’s Complex Figurewas used and to assess set-shifting the Strooptest, the Trail Making Test B and the PhonologicalFluency test were used. Demographicand clinical aspects such as age, educationallevel, body mass index, anxiety, depression,obsessive-compulsive and eating disorderrelated symptoms were also evaluated.First-degree relatives of patients withanorexia nervosa showed lower performanceon measures of central coherence (p