Bipolar II disorder is a mood disorder. The primary feature of bipolar II disorder is alternating periods of depressed and hypomanic moods. The periods of hypomania are less severe than the mania found in bipolar I disorder. The fluctuating moods are different than the ups and downs of usual life.
Depression
One criteria of bipolar II disorder is having at least one major depressive episode in the past or at the present time. According to the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM), someone experiencing a major depressive episode has a depressed mood or decreased interest or pleasure in doing enjoyable things. These symptoms are accompanied by insomnia or sleeping too much, excessive fatigue, changes in appetite or weight, feeling restless or slowed down, hopelessness or worthlessness, feeling guilty, concentration difficulties, indecisiveness, or having thoughts of suicide or death. To meet criteria for a major depressive episode, these symptoms must last at least two weeks.
Hypomania
Individuals with bipolar II disorder also have hypomanic episodes. The DSM criteria for a hypomanic episode include feeling very elated, euphoric or irritable. Individuals with bipolar II disorder may also have grandiose ideas, need little sleep, be very talkative or have rapid speech, have racing thoughts, are easily distracted, or are hyperactive. These symptoms last at least four days to meet criteria for a hypomanic episode. The symptoms are notable, as they are observable to others and do not occur for a person except during a hypomanic episode. However, hypomanic episodes are less severe than manic episodes found in bipolar I disorder.
Mood Cycling
Individuals with bipolar II disorder alternate having a major depressive episode with a hypomanic episode. Some people cycle back and forth between depressive and hypomanic episodes, while others experience periods of no depression or hypomania between episodes. Individuals experiencing at least four depressive or hypomanic episodes within a year are considered to be rapid-cycling, according to the DSM. Rapid-cycling is more common among women than men and among individuals with bipolar II disorder than other subtypes of bipolar disorder, as found in a study by Kupka in the December 2003 issue of the "Journal of Clinical Psychiatry."
Prevalence
About 0.5 percent of the general population (about 1.5 million in the United States) has bipolar II disorder in their lifetime, according to a study by Judd in the January 2003 issue of "The Journal of Affective Disorders." The number of people with bipolar II disorder is similar between men and women.
Difference Between Bipolar II Disorder and Bipolar I Disorder
Although bipolar I disorder and bipolar II disorder are marked by mood fluctuations, they differ in the severity of the manic moods. In bipolar II disorder, major depressive episodes alternate with hypomanic, whereas major depressive episodes alternate with manic episodes in bipolar I disorder. A manic episode lasts longer than a hypomanic episode and the manic symptoms may be severe enough to require hospitalization.
References
- "Diagnostic and Statistical Manual of Mental Disorders (4th ed. Text Revision);" American Psychiatric Association; 2002
- "Journal of Affective Disorders;"; The Prevalence and Disability of Bipolar Spectrum Disorders in the U.S. Population: Re-Analysis of the ECA Database Taking into Account Subthreashold Cases; Lewis Judd and Hagop Akiskal; January 2003
- "Journal of Clinical Psychiatry"' Rapid and Non-Rapid Bipolar Disorder: A Meta-Analysis of Clinical Studies; Ralph Kupka, David Luckenbaugh, Robert Post, Gabriele Laverich, and Willem Nolen; December 2003
