Bipolar Disorders: Mixed States, Rapid-Cycling, and Atypical Forms

95 Bipolar I and bipolar II: a dichotomy?Several studies have reported a higher risk of suicide in bipolar II patients(Dunner et al., 1976; Stallone et al., 1980; Dunner, 1983; Goldring and Fieve,1984; Arató et al., 1988). Rihmer and Pestality (1999) reviewed the rate of lifetimehistory of suicide attempts and found it was attempted by 17% of bipolar Ipatients, 24% of bipolar II patients, and 12% of unipolar major depressivepatients. In addition, bipolar II patients were relatively overrepresented amongsuicide victims. It was not only the personal history of suicide attempts, but alsothe family history of completed suicide in first-degree relatives that was significantlyhigher in bipolar II patients as compared to unipolar major depressives(Rihmer, 2002). Interpersonal conflicts, marital instability, and/or family breakdownwere found to be particularly more frequent among bipolar II patients withrespect to bipolar I and unipolar depressive patients, which, in the opinion of theauthors, might contribute to the high suicidality. Kupfer et al.(1988) found higherpast suicide attempts in a group of bipolar II patients than in a group of unipolardepressive patients.Other authors have shown that bipolar II patients with personality disordershad a higher suicidal risk (Vieta et al., 1999). The presence of comorbidity seemedto have no relevant impact on the clinical course of bipolar II patients except forsuicidality (Vieta et al., 2000). Previous studies did not show significant differencesbetween bipolar I and bipolar II patients with respect to suicidal behavior (Coryellet al., 1989; Vieta et al., 1997b). These discrepancies may be due to differentdefinitions of bipolar II disorder, biases derived from the setting, and comorbidity.In fact, it has been suggested that the exclusion of personality traits and substanceabuse might eliminate some of the differences between bipolar I and bipolar IIpatients (Cooke et al., 1995). There is some evidence that bipolar II disorder ismore likely than unipolar disorder or bipolar I disorder to occur with otherpsychiatric diagnoses (Endicott et al., 1985).PathophysiologyUnfortunately, most of the studies do not compare bipolar I and bipolar IIdisorders. We will comment on some of the studies that take into account bipolarsubtypes.Family studies and geneticsFamily studies are useful for an understanding of the pathophysiology of bipolardisorders and then to evaluate the dimensional model and the category model.Some studies have concluded that bipolar II patients seem to have more bipolar IIand unipolar relatives and fewer bipolar I relatives than bipolar I patients do(Coryell et al., 1984; Fieve et al., 1984). Coryell et al. (1984) not only found that