any of a group of mood disorders in which symptoms of mania and depression alternate. In DSM–IV–TR and DSM–5, the group includes primarily the following subtypes: bipolar I disorder, in which the individual fluctuates between episodes of mania or hypomania and major depressive episodes or experiences a mix of these: bipolar II disorder, in which the individual fluctuates between major depressive and hypomanic episodes; and cyclothymic disorder. 

in DSM–IV–TR and DSM–5, a personality disorder characterized by a long-standing pattern of instability in mood, interpersonal relationships, and self-image that is severe enough to cause extreme distress or interfere with social and occupational functioning.

in DSM–IV–TR and DSM–5, a disturbance involving the sudden onset of at least one psychotic symptom (e.g., incoherence, delusions, hallucinations, or grossly disorganized or catatonic behavior). 

an eating disorder involving recurrent episodes of binge eating (i.e., discrete periods of uncontrolled consumption of abnormally large quantities of food) followed by inappropriate compensatory behaviors (e.g., self-induced vomiting, misuse of laxatives, fasting, excessive exercise).