Abnormalities in brain activation using functional magnetic resonance imaging (fMRI) during cognitive and emotional tasks have been identified in bipolar disorder patients, in frontal, subcortical and limbic regions. Several studies also indicate that mood state may be differentiated by lateralization of brain activation in fronto-limbic regions. The interpretation of fMRI studies in bipolar disorder is limited by the choice of regions of interest, medication effects, comorbidity, and task performance. These studies suggest that there is a complex alteration in regions important for neural networks underlying cognition and emotional processing in bipolar disorder. However, measuring changes in specific brain regions does not identify how these neural networks are affected. New analytical techniques of fMRI data are needed in order to resolve some of these issues and identify how changes in neural networks relate to cognitive and emotional processing in bipolar disorder.

Using the family history method, we assessed the morbid risk for psychiatric disorders the first-degree relatives of 69 probands with bulimia, 24 probands with major depression, and nonpsychiatric control probands. The morbid risk for major affective disorder among the first-degree relatives of the bulimic probands was 32%, significantly greater than that found in the nonpsychiatric control probands. The rate of familial major affective disorder was significantly greater in bulimic probands who had a history of major affective disorder themselves than in bulimic probands without such a history - but the latter group, in turn, displayed significantly higher rates than the nonpsychiatric control probands. Eating disorders were slightly, but not significantly, more prevalent in the families of bulimic probands than nonpsychiatric control probands. We present two alternative hypotheses which might explain these findings.

The 420 first-degree relatives of 14 patients with anorexia nervosa, 55 patients with bulimia, and 20 patients with both disorders were evaluated for the presence of psychiatric illness, using DSM-III criteria, by the family history method. The morbid risk for affective disorder in the families of the eating disorder probands was similar to that found in the families of patients with bipolar disorder; but was significantly greater than that found in the families of patients with schizophrenia or borderline personality disorder. These results add to the growing evidence that anorexia nervosa and bulimia are closely related to affective disorder.