Set shifting impairments in an outpatient eating disorder sample
Swanson, Helen M.
Background: Patients with anorexia nervosa have been consistently reported to show impairments in set shifting ability. Such deficits may be associated with characteristics commonly observed in this patient group, such as obsessive thoughts and behaviours around eating, maladaptive problem solving and a rigid thinking style. Objective: Much of the preceding literature on set shifting ability has involved inpatient samples meeting strict diagnostic criteria for anorexia nervosa. However most eating disorder patients are outpatients and commonly do not meet full criteria for anorexia nervosa. This study thus aimed to investigate the relationship between set shifting ability and psychological characteristics in a community sample of outpatients with symptoms of anorexia nervosa. Methods: Performance on selected measures of set-shifting ability (Wisconsin Card Sort Test, WCST; Delis-Kaplan Executive Function System, Hayling & Brixton) were compared between an eating disorders group comprising 17 female outpatients with symptoms of anorexia nervosa and a control group comprising 27 students. Set shifting performance was then correlated with eating disorder severity (Eating Disorders Examination), obsessive-compulsive symptoms (Yale-Brown Obsessive Compulsive Scale), and the Social Problem Solving Inventory. Results: The eating disorder group demonstrated significantly worse set shifting ability than the healthy control group on the primary outcome measure (WCST), with 47% of eating disorder participants showing impairment on this measure. Severity of obsessive-compulsive symptoms and an impulsive and careless approach to problem solving were associated with poorer scores on the WCST in the eating disorder group. Although the eating disorder group were significantly more impaired in set shifting than controls, set shifting ability was not associated with eating disorder severity. Conclusions: The results indicate that set shifting impairments are present in outpatients with eating disorders with anorexic symptoms, and may be trait characteristics. Impaired set shifting was associated with obsessive-compulsive symptoms and maladaptive problem solving. These findings highlight a need for neuropsychological assessment of eating disorder outpatients in order to identify individuals who may benefit from psychological interventions to reduce the impact of these impairments.