Bipolar I Disorder: With this form, people have one or more episodes of intense highs (mania) and/or lows (depression). Some people also lose touch with reality and experience psychotic thinking during episodes of mania.

Mixed Bipolar State: With this form, symptoms of mania and depression occur together. Manic episodes and major depressive episodes (e.g. sadness, irritability, euphoria) rapidly alternate for at least a week. Symptoms can include agitation, insomnia, change in appetite, psychotic features, and suicidal thinking. Mood disturbance is severe enough to noticeably impair the ability to function at work or conduct social relationships. If harm may be caused to oneself or to others, hospitalization may be necessary.

Psychotic Features: Common psychotic features, seen in severe episodes of mania or depression, are hallucinations and delusions. When people hallucinate, they may see, hear, or otherwise sense the presence of things not actually there. Delusions occur when people hold false, strongly held beliefs not influenced by logical reasoning or explained by a person's usual cultural concepts.

Rapid-Cycling Bipolar Disorder: With this form, people experience four or more episodes of highs (hypomania or mania) and lows (depression) within a 12-month period.