I read with interest the article by Drs Thompson-Brenner and Westen (Reference Thompson-Brenner and Westen2005) about personality subtypes in eating disorders. Subnutrition from any cause is known to impair cognitive function and several workers have identified this in connection with anorexia nervosa (Reference MacdonaldMacdonald, 1995).

The authors give no data on body mass index or weight. However, 38% of their sample had met criteria for anorexia nervosa at some point, 56% were fasting 4 days a week and half were exercising excessively. It is likely therefore that cognitive impairment was present in many. Hence the ‘personality subtypes’ identified may vanish on refeeding, or may be more pronounced, having been masked by cognitive blunting. It seems best to seek for personality subtypes in eating disorders during periods of adequate nutrition.