What is the difference between Bipolar I and Bipolar II disorder?

Bipolar I disorder is characterized by the occurrence of at least one manic episode. This manic episode may be preceded or followed by hypomanic episodes or major depressive episodes. However, the presence of at least one manic episode is the defining feature of Bipolar I, which distinguishes it from other mood disorders.

In contrast, Bipolar II disorder is defined by the presence of at least one major depressive episode and at least one hypomanic episode, but it does not include a full manic episode. Therefore, individuals with Bipolar II do not experience the same severe manic episodes that characterize Bipolar I.

The clarity around the manic episode requirement is crucial in differentiating the two disorders. Recognizing this distinction allows clinicians to provide accurate diagnoses and effective treatment plans tailored to the individual's experiences.