Introduction: Bipolar II disorder seems to be more than a mild form of classic manic-depressive illness. Differences with bipolar I concern genetic, biological, clinical and pharmacological aspects. Nevertheless, studies on suicidal behavior in both groups have resulted in inconsistent results
Patients and method: Twenty-two patients fulfilling Research Diagnostic Criteria for the diagnosis of bipolar II disorder and 38 bipolar I were evaluated with the Schedule for Affective Disorders and Schizophrenia by two independent interviewers, and compared.
Results: Bipolar II patients had significantly more previous episodes (p = 0.001), including both depressive (p = 0.003) and hypomanic switches (p = 0.006), but had been hospitalized (p = 0.001) and presented psychotic symptoms (p < 0.001) less frequently.
Conclusions: There were no significant differences between both groups regarding suicidal behavior variables. These results suggest that bipolar II disorder is less severe than bipolar I regarding symptoms intensity, but more severe with respect to episodes frequency, and that suicide attempts rates are not useful to discriminate between both groups.