The main differences between Bipolar 1 and Bipolar 2 disorders lie in the severity and type of mood episodes experienced:
- Bipolar 1 Disorder is characterized by at least one full manic episode, which is a period of abnormally elevated, expansive, or irritable mood lasting at least one week. These manic episodes are severe enough to cause significant impairment in social or occupational functioning or require hospitalization. Depressive episodes may also occur but are not required for diagnosis
- Bipolar 2 Disorder involves at least one hypomanic episode and at least one major depressive episode. Hypomania is a milder form of mania lasting at least four days, without causing severe impairment or hospitalization. Bipolar 2 does not include full manic episodes. Depressive episodes tend to be longer and more frequent in Bipolar 2, often dominating the clinical picture
Additional distinctions include:
- Impact on daily life: Bipolar 1 manic episodes can lead to impulsive behaviors and significant disruption, while Bipolar 2's main challenge is often the prolonged depressive phases that affect motivation and functioning
- Diagnosis criteria: Bipolar 1 requires at least one manic episode; Bipolar 2 requires at least one hypomanic and one major depressive episode
- Genetic and clinical differences: Research indicates Bipolar 1 is associated with a higher genetic risk load for schizophrenia and more severe manic symptoms, while Bipolar 2 carries a higher genetic risk for depression and more frequent depressive episodes
In summary, Bipolar 1 involves severe manic episodes and may or may not include depression, whereas Bipolar 2 involves milder hypomania and prominent depressive episodes without full mania
