What Is the Difference Between Bipolar I and Bipolar II Disorders?

Question: What Is the Difference Between Bipolar I and Bipolar II Disorders?

Answer: The most important distinctions between Bipolar I and II are:

1. A person with BP II experiences hypomanic episodes but not manic episodes. The difference between mania and hypomania is a matter of severity - hypomania generally does not impair a person's daily functioning or cause the need for hospitalization.

2. Experience of psychotic symptoms such as hallucinations or paranoia indicates Bipolar I Disorder; the presence of such symptoms rules out Bipolar II.

Another difference noted in the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, which is the standard used in the United States, is that in Bipolar II disorder there are no mixed episodes. Our experience tells us that mixed episodes are extremely common in Bipolar II. This is undoubtedly a point for consideration in future editions of this manual.