Bipolar I Disorder 131
Suicide Risk
The lifetime risk of suicide in individuals with  bipolar disorder is estimated to be at least
15 times that of the general population. In fa ct, bipolar disorder may account for one-quar-
ter of all completed su icides. A past history of suicide attempt and percent days spent de-
pressed in the past year are associated with gr eater risk of suicide attempts or completions.
Functional Consequences of Bipolar I Disorder
Although many individuals with bipolar disord er return to a fully functional level be-
tween episodes, approximately 30%  show severe impairment in  work role function. Func-
tional recovery lags substantially behind reco very from symptoms, especially with respect
to occupational recovery, resulting in lower socioeconomic status despite equivalent lev-
els of education when compared with the ge neral population. Individuals with bipolar I
disorder perform more poorly than healthy in dividuals on cognitive tests. Cognitive im-
pairments may contribute to vocational and interpersonal difficulties and persist through
the lifespan, even during euthymic periods.
Differential Diagnosis
Major depressive disorder. Major depressive disorder may also be accompanied by hy-
pomanic or manic symptoms (i.e., fewer symptoms or for a shorter duration than required
for mania or hypomania). When the individual presents in an episode of major depression,
one must depend on corroborating history re garding past episodes of mania or hypoma-
nia. Symptoms of irritability may be associated with either major depressive disorder or
bipolar disorder, adding to  diagnostic complexity.
Other bipolar disorders. Diagnosis of bipolar I disorder is differentiated from bipolar II
disorder by determining whether there have be en any past episodes of mania. Other spec-
ified and unspecified bipolar and related disord ers should be differentiated from bipolar I