Hypothesised neuropsychological causes for an observed deficit in motor performance on a computer game in women with bulimia were tested. Subjects were 19 normal weight women with bulimia nervosa participating in a cognitive-behavioural treatment trial, and 19 healthy controls matched for age and IQ in a yoked pre- and post-treatment design. Measures of global impulsivity, motor impulsivity and response inhibition failed to show bulimic women as more impulsive than controls, and failed to support motor impulsivity as a cause of the observed deficit. Results failed to support an attention deficit, slowed motor speed or a visuo-spatial-motor deficit as responsible for the observation, but reaction time was found to be significantly slowed in the women with bulimia. Differences in reaction time were primarily a function of depression and not pathognomonic of bulimia per se.