The standard for a diagnosis of bipolar disorder is the presence of a manic episode, though the vast majority will experience depression as part of the disorder.
A manic episode is a sustained period of “abnormally and persistently elevated, expansive, or irritable mood” in a distinct shift from normal functioning—not just “10 minutes of feeling super-good,” as one clinician puts it, but a pattern of behavior. Some of the following symptoms are also usually present: grandiosity; decreased need for sleep; increased talkativeness; racing thoughts; scattered attention; drive to achieve goals; and risk-taking behavior. These symptoms must significantly interfere with normal activities—social life, school, work—or a psychotic episode must be present.
A teenager in a major depressive episode will display either depressed or irritable mood most of the time, or lose interest or pleasure in things he once enjoyed. In addition, he’ll show some of the following symptoms: marked weight loss or gain; sleeping too much or too little; restlessness or lethargy; fatigue; feelings of hopelessness, helplessness, worthlessness, or excessive or inappropriate guilt; cloudy or indecisive thinking; and a preoccupation with death, plans of suicide, or an actual suicide attempt.
This section describes the most severe form of the condition, called bipolar I disorder. Some are also diagnosed with bipolar II disorder, in which less severe episodes of hypomania replace manic episodes.