Bipolar II is a psychological disorder that involves periods of hypomania, which is a less severe form of mania, and depression. The distinction of bipolar II as a separate disorder is relatively new, but the distinction from bipolar I is very important. According to studies conducted at the University of Washington during the last three decades, very few individuals with bipolar II ever have a manic episode. This indicates that bipolar II is not just an early stage of bipolar I. The disorder is frequently undiagnosed or misdiagnosed for many reasons including its similarities between unipolar depression, bipolar I and cyclothymic disorder.
Hypomania
Hypomanic episodes are distinct periods of mood elevation or irritability lasting at least four days. In contrast with mania, which is characteristic for bipolar I, hypomania does not usually require hospitalization or cause significant impairment in social and occupational functioning. According to the American Psychiatric Association (APA), 60 to 70 percent of hypomanic episodes immediately follow depression episodes, meaning there are few periods of remission for those with bipolar II. Individuals in a hypomanic episode generally experience an inflated self-esteem, need little sleep, are flooded with new ideas and thoughts, are easily distracted, feel very productive in projects and tasks and become involved in pleasurable, but risky, activities such as sexual indiscretions. Unlike bipolar I, they are unlikely to experience psychotic symptoms during either a depression or hypomanic episode.
Bipolar II has the potential to be misdiagnosed as a personality disorder because of the emotional labiality between episodes, which is characteristic of those with borderline or histrionic personality disorders. In adolescents and adults, it can also be misdiagnosed as attention-deficit hyperactivity disorder because of the distractibility and excessive energy displayed.
Depression
According to the APA, individuals with bipolar II experience more depression episodes than those with bipolar I disorder. Individuals in a depression episode, also called a major depressive episode, may experience a lack of interest in activities that were previously enjoyable, feel fatigue, have a change in sleeping and eating patterns, experience suicidal thoughts and display inappropriate guilt or worthlessness. According to Dr. David L. Dunner, a researcher a the University of Washington, studies suggest that those with bipolar II are more likely to cycle with the seasonal weather patterns than those with bipolar I or unipolar depression. They often experience hypomanias in spring and summer and depression symptoms in the fall and winter months. This suggested a connection among amounts of light, sleep-wake cycles and episodes experienced.
Suicide Risks
Individuals with bipolar II have a higher risk of suicide than those with bipolar I and unipolar depression. A summary of several research studies cited by the APA indicates that 24 percent of those with bipolar II contemplate suicide or make attempts, compared with 17 percent of those with bipolar I disorder. One explanation for the high suicide rates is misdiagnosis. Antidepressants are often prescribed to those who are misdiagnosed, and these drugs can often increase cycling between episodes.
References
- Diagnostic and Statistical Manual of Mental Disorders Fourth Edition Text Revision, 2000
- Oxford Textbook of Psychopathology, 1999
- "Bipolar II Disorder: Symptoms, Course, and Response to Treatment," Psychiatric Services, by Glenda MacQueen, MD, PhD and Trevor Young, MD, PhD 2001
