What Is the Difference Between Bipolar I and Bipolar II?

Many people don’t know it, but there are multiple types of bipolar disorder and this article is designed to explore the differences between bipolar I and bipolar II. Bipolar I (also known as bipolar disorder type I or bipolar 1) and bipolar II (also known as bipolar disorder type II or bipolar 2) both affect about one percent of the population of the United States with bipolar II being the slightly more prevalent mental illness. Both types of bipolar disorder can be incredibly disabling but both can also be managed with medication, therapy and lifestyle changes.

Bipolar disorder type I contains severely elevated or irritable episodes known as manias alongside deep depressions. Bipolar disorder type II, on the other hand, contains elevated or irritable episodes that are less severe and known as hypomanias alongside its deep depressions.

Bipolar Disorder Type I and Bipolar Disorder Type II Similarities

Bipolar disorder I and bipolar disorder II are sort of like fraternal twins – most of their DNA is the same. For bipolar disorder type I and bipolar

disorder type II, the following are the same:

• Both types of bipolar disorder are mental illnesses as defined in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5).
• Both types of bipolar disorder are considered serious mental illnesses.
• Both types of bipolar disorder experience the same major depression symptoms and episodes.
• Both types of bipolar disorder can experience mood episodes with mixed features wherein elevated or irritated and depressed symptoms occur together.
• Both types of bipolar disorder are diagnosed primarily through personal interviews.
• Both types of bipolar disorder are treated with the same types of medication: primarily anticonvulsants, antipsychotics and mood stabilizers.
• Both types of bipolar are treated with the same types of therapy such as cognitive behavioral therapy, interpersonal/social rhythm therapy and family-focused therapy.

Differences Between Bipolar Disorder Type I and Type II

One of the most important differences between bipolar I and bipolar II is the fact that psychosis can occur in bipolar disorder type I mania but not in bipolar disorder type II hypomania, by definition. (Psychosis is the presence of delusions [false beliefs held in spite of contrary evidence] and hallucinations [false experiences with any sense].) Psychotic symptoms can occur in bipolar disorder type I or type II depressions, however.

Other differences between bipolar I and bipolar II include:

• Bipolar disorder type II occurs more frequently in women ("How Bipolar Disorder Symptoms Affect Women Uniquely").
• Those with bipolar disorder type I are often hospitalized during a manic episode whereas those with bipolar type II are typically first seen and treated while in a depression.
• Those with bipolar disorder type I should not be treated with an antidepressant alone as they have a greater risk of switching into a mania as a reaction to an antidepressant.

There may be additional differences between bipolar I and bipolar II that are not yet known due to lack of research comparing some aspects of the two illnesses.

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