With bipolar I, a person may experience a manic episode of extreme highs lasting around seven days or requiring hospitalization. This may or may not be followed by an extremely depressed period lasting around two weeks.
With bipolar II, a person may experience a less-intense version of mania called hypomania, which is not as severe as bipolar I. A depressive episode may occur before or after the hypomania. This depressive state can be severe. Therefore one condition of bipolar is not more or less serious than another.