Compulsive exercise to control shape or weight in eating disorders: prevalence, associated features, and treatment outcome.

OBJECTIVE

The study was aimed at assessing the prevalence of compulsive exercising to control shape and weight in eating disorders (EDs) and its relationship with treatment outcome.

METHOD: Compulsive exercising to control shape and weight, defined according to a modified version of the Intense Exercising to Control Shape or Weight section of the Eating Disorder Examination (EDE), was assessed in 165 consecutive ED inpatients entering a protocol based on the transdiagnostic cognitive behavior theory and treatment of EDs. Baseline assessment also included anthropometry, the global EDE interview, the Beck Depression Inventory, the State-Trait Anxiety Inventory (STAI), the Eating Disorders Inventory-Perfectionism Scale, and the Temperament and Character Inventory.

RESULTS

Of the patients, 45.5% were classified as compulsive exercisers, the prevalence being highest (80%) in restricting-type anorexia nervosa (AN), lowest in EDs not otherwise specified (31.9%), and intermediate in binge/purging AN (43.3%) and in purging-type bulimia nervosa (39.3%). Compulsive exercising to control shape and weight was independently predicted by the EDE restraint score (odds ratio, 1.32; 95% confidence interval, 1.06-1.64; P = .014) after adjustment for ED; the total amount of exercise was associated with EDE restraint, as well as with the Temperament and Character Inventory reward dependence. At follow-up, an improved EDE global score was predicted by lower baseline values, higher baseline STAI and STAI improvement, and lower amount of exercise in the last 4 weeks. Voluntary treatment discontinuation was not predicted by baseline exercise.

DISCUSSION: Compulsive exercising to control shape and weight is a behavioral feature of restricting-type AN, associated with restraint and temperament dimensions, with influence on treatment outcome.