Brain glucose metabolism in anorexia nervosa and affective disorders: influence of weight loss or depressive symptomatology.

Relationships between eating and affective disorders remain complex and unclear. Brain glucose metabolism of anorectic patients has been demonstrated to be reduced both globally and regionally, with a particular relative hypometabolism in the parietal cortex. To explore the possible influence of weight loss or depressive symptomatology on brain metabolism, we studied age- and sex-matched low-weight anorectic and depressed patients, normal-weight depressed patients, and healthy volunteers. Absolute global and regional glucose activity levels were reduced in low-weight patients, with the lowest values being found for anorectic patients. In relative values, anorectic patients showed a significant parietal hypometabolism in comparison to control subjects while they had higher metabolism in the caudate nuclei when compared with the other groups. Absolute hypometabolism of glucose seems to be a consequence of low weight as it was found in both low-weight anorectic and low-weight depressive patients. In addition, absolute glucose values were significantly correlated with body mass index in all subjects. Future positron emission tomographic studies in psychiatric patients should control for alimentary parameters.