A controlled family history study of bulimia.

Using the family history method, we assessed the morbid risk for psychiatric disorders in the first-degree relatives of 69 probands with bulimia, 24 probands with major depression, and 28 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.