[Comorbidity of bipolar and eating disorders. Epidemiologic and therapeutic aspects]

The frequent association of bulimia nervosa and affective disorders is well documented. Most studies on this topic have focused on the comorbidity of bulimia nervosa and unipolar depression. The literature on the comorbidity of eating disorders and bipolar disorder is more sparse. Nevertheless, an increased rate of bipolar disorder, especially bipolar II disorder, has been found by several epidemiological studies in patients with bulimia nervosa. This association might be more frequent in bulimic patients presenting with a severe chronic type of eating disorder. The relatives of bulimic patients also display an increased morbid risk for bipolar disorder. Although the comorbidity of bulimia and bipolar disorder does not appear coincidental, the nosological relationships between these two disorders are not perfectly clear. The possible relationships between seasonal affective disorders and bulimia nervosa have recently been suggested by some epidemiological studies, demonstrating that bulimia may display seasonal variations with winter worsening of bulimic symptoms. Eating symptoms are present in both winter depression and bulimia nervosa. The carbohydrate craving encountered in the former disorder could be compared to "binge eating" in bulimic patients. Epidemiological data suggest that winter depression is most frequently part of a bipolar II disorder. Few data are available concerning the therapeutic implications of the association of bulimia nervosa and bipolar disorder. Some case reports of concomitant remission of both disorders with anticonvulsivants or lithium salts have been published. However, there are no controlled studies. Anticonvulsivants or lithium salts might be indicated in some bulimic patients who do not present with a typical bipolar disorder, but who fulfill clinical criteria which are potentially predictive of a good response to such medications.