Which statement is true about bipolar I vs bipolar II in manic episodes?

• A. It excludes depressive episodes
• B. It is defined by rapid mood cycling
• C. It requires at least one manic episode
• D. It requires hypomanic episodes only

Answer: (C)

The key idea is that having a manic episode is what defines bipolar I. A manic episode is a period of abnormally elevated or irritable mood with increased energy, lasting at least seven days (or any duration if hospitalization is required) and causing clear impairment or hospitalization. Bipolar I requires at least one manic episode; depressive episodes can occur but are not required. Bipolar II, in contrast, involves hypomanic episodes plus major depressive episodes, with no full manic episode ever occurring. Rapid mood cycling can happen for some individuals but is not what distinguishes bipolar I from bipolar II. So the statement that it requires at least one manic episode is the accurate description.