Bipolar disorder is characterized by unpredictable swings in mood from mania (or hypomania) to depres- sion. Some patients suffer only from recurrent attacks of mania, which in its pure form is associated with increased psychomotor activity; excessive social extroversion; decreased need for sleep; impulsivity and impaired judgment; and expansive, grandiose, and sometimes irritable mood (Table 444-8). In severe mania, patients may experience delusions and paranoid thinking indistinguishable from schizophrenia.