Hyperinsulinemia; a mediator of decreased food intake and weight loss in anorexia nervosa and major depression.

Decreased food intake and weight loss are seen in eating and depressive disorders. No satisfactory pathophysiological mechanisms have been proposed to explain those findings. While it should be kept in mind that the etiology of those diseases is still unclear, it seems reasonable to propose that the maintenance of anorectic behavior in the eating disorders as well as the decreased food intake of major depression, leading to continued weight loss seen in both conditions, are either caused or mediated by insulin in levels which are elevated but insufficient to cause hypoglycemia. A brief review is made of the role of insulin in satiety and in the control of body weight, and of the newly available techniques to accurately quantify secretion, hepatic extraction, and post-hepatic delivery rates of insulin. Neural, metabolic, and endocrine stimuli affect insulin secretion. The hypothesis is therefore compatible with several etiologic factors leading to hyperinsulinemia in anorexia nervosa and major depression, and resulting in decreased food intake and weight loss.