Evaluation of many depressed patients has revealed biphasic characteristics, and 1 in 5 of those with depression also have significant mild manic or manic manifestations. Most patients change from monophasic to biphasic disorder within 5 years after the onset of depressive manifestations. Indications for change include early onset of depression (<25 years), postpartum depression, frequent episodes of depression, rapid improvement in mood after somatic treatment (e.g., antidepressants, light therapy, sleep deprivation therapy, electroconvulsive therapy), and a family history of mood disorders for three consecutive generations. In between episodes, patients with bipolar disorder are depressed and sometimes hyperactive; impairments in developmental and social functioning are more common than in monophasic disorder. Bipolar disorder has a shorter onset (3-6 months), an earlier onset, a more abrupt onset, and a shorter cycle (time between episodes) than monophasic disorder. The rapid cycling form of bipolar disorder is particularly notable for its onset cycle (often more than 4 episodes per year). Patients with bipolar I disorder alternate between full mania and major depression. It often starts as a depressive form with at least one more manic or euphoric phase in the course of the illness. The depressive phase can be either immediately before or after the manic phase, or months or years apart from the manic phase. In bipolar II disorder, depression and hypomania (relatively mild, nonpsychotic periods usually under 1 week) alternate. During the hypomanic phase, the patient's mind is bright, the need for sleep is diminished, and psychomotor activity exceeds the patient's usual level. Conversion is often influenced by circadian rhythmic factors (e.g., depression at bedtime and a light manic state upon awakening in the early morning). Sleepiness and overeating are typical and can recur seasonally (e.g., in autumn or winter); insomnia and poor appetite may occur during the depressive phase. Hypomania is adaptive for some patients, as patients feel energized, confident, and hyperfunctional socially. Many patients tend to feel elevated at the end of a depressive episode, but patients will not voluntarily communicate this change in state of mind unless specifically asked by the physician. Using questioning techniques, many signs of illness such as profligacy, impulsive promiscuity, and stimulant abuse can be identified during question and answer sessions. Relatives of the patient are more likely to provide this information. Patients with major depressive episodes and a family history of bipolar disorder (commonly known as bipolar III) often exhibit a mild tendency toward hypomania; this trait is called affective hyperactivity (i.e., urgency, ambition, and pursuit of fame and fortune).