bipolar disorder

or manic-depressive psychosis

Mental illness characterized by the alternation of manic and depressive states. Depression is the more common symptom, and many patients experience only a brief period of overoptimism and mild euphoria during the manic phase. The condition, which seems to be inheritable, probably arises from malregulation of the amines norepinephrine, dopamine, and 5-hydroxytryptamine. It is most commonly treated with lithium carbonate.

Find more information on bipolar disorder. Upgrade to Britannica Online for more on bipolar disorder.