Set-shifting abilities, central coherence, and handedness in anorexia nervosa patients, their unaffected siblings and healthy controls: exploring putative endophenotypes.

OBJECTIVE: There is consistent evidence that anorexia nervosa (AN) is associated with an impairment of set-shifting abilities and central coherence. No study to date investigated handedness in AN. Our aim was to study set-shifting abilities, central coherence, and handedness in subjects with lifetime AN, in a sample of unaffected sisters and in healthy controls, in order to explore their suitability as endophenotypes of AN. METHODS: The Edinburgh Handedness Inventory and several neuropsychological tasks (Wisconsin Card Sorting Test, Trail Making Test, Rey-Osterrieth Complex Figure Test, Overlapping Figures Test, Object Assembly and Block Design) were administered to 153 subjects with lifetime AN, 28 unaffected sisters and 120 healthy controls. RESULTS: AN subjects and their healthy sisters showed poorer performances on most tasks investigating set-shifting and central coherence. In addition, we did not find any differences between long-term recovered subjects, weight-restored AN patients and those in an acute phase of their illness. AN subjects were significantly more likely to be left-handed than healthy controls (OR=2.8, 95% C.I. 1.1-7.2). CONCLUSIONS: Set-shifting and central coherence seem to be promising cognitive endophenotypes that might help in the understanding of the pathogenetic processes involved in AN. Further studies on larger samples are needed to explore the generalizability and implications of our findings concerning handedness.