Performance variability as a new theoretical mechanism regarding eating disorders and cognitive processing.

Bulimic (n = 23) and control subjects (n = 28) were compared on four neuropsychological tests and several clinical variables. Between-group differences were observed on neuropsychological measures that reflected marked impulsivity and problem-solving deficits in the bulimics. Additional between-group comparisons, based on the variability of performance on the neuropsychological tests, revealed that bulimics were more variable than controls on approximately 50% of the tests given Performance variability on the remaining two tests was equal across the bulimic and control groups. This represents the first known application of this performance variability analysis in subjects with bulimia nervosa. It is proposed that there may be considerable variability in performance among bulimics and that by examining performance from this "sub-group" perspective may lead to a more analytic understanding of this eating disorder.