What does it mean if someone has both severe depression and manic episodes?

Bipolar: If someone is having episodes of both depression and mania, then they likely have bipolar disorder. They should be diagnosed by a mental health professional as treatment for bipolar disorder is different than for depression alone.

Bipolar: Bipolar I and bipolar II, In the first, manic phases are more severe, and in the second, depressive phases are more severe. There is also cyclothymia which is a low grade version of bipolar disorder in general, where mood swings are not as severe in either direction, manic or depressive.