What is a key difference between Bipolar I and Bipolar II disorders?

Bipolar I disorder is characterized by the presence of at least one manic episode, which is often severe and can significantly impair a person’s functioning. These manic episodes may alternate with periods of depression, which can also be severe, making the disorder complex and challenging to manage. The key distinction here is that Bipolar I is defined by the occurrence of manic episodes, which are more intense and can lead to hospitalization or legal issues due to their severity.

In contrast, Bipolar II disorder involves a pattern of depressive episodes and hypomanic episodes, which are less severe than the manic episodes seen in Bipolar I. While both disorders can include depressive episodes, Bipolar II does not have the full-blown manic episodes that characterize Bipolar I. Therefore, the correct answer highlights that Bipolar I involves severe mood episodes that range from mania to depression, emphasizing the significant mood elevation and its impacts, which is central to understanding these disorders' differences.