Bipolar disorder, previously called manic depression, is characterized by alternating periods of elation and depression. Bipolar depression is not a diagnosis in itself, but instead it refers to the periodic depressive episodes that individuals with this disorder experience.
Bipolar disorders consists of at least one episode of mania or hypomania (over-elevated mood) and at least one episode of major depression. Bipolar I is characterized by periods of mania and requires only one major depressive episode to meet the criteria. Bipolar II, on the other hand, is characterized by depressive episodes, and only one manic or hypomanic period is required to meet the criteria.
Prevalence and Specific Features of Bipolar Disorders
According to the American Psychiatric Association, 0.5 percent to 1.5 percent of the population has either bipolar I or bipolar II disorder. For both bipolar I and II, individuals who have a first-degree blood relative with the disorder are more likely to get it themselves. Men are more likely to be diagnosed with bipolar I and women with bipolar II. For both men and women, the age of onset is usually in the early 20s. An onset of bipolar symptoms after age 40 is rare and might signify either substance use or the presence of another general medical condition.
Criteria for Depressive Episodes in Bipolar Disorder
Bipolar disorders require at least one major depressive episode, which is characterized by intense physical and psychological symptoms of depression nearly every day for at least two weeks. Symptoms can include feelings of hopelessness, emptiness, excessive guilt, low self-esteem, fatigue, unplanned weight change of at least 5 percent of body weight within one month, and a change in sleep patterns such as the onset of insomnia or excessive sleeping. In addition, slowed motor skills or motor agitation, significant disturbance in concentration and memory, and recurrent thoughts of death can also be symptoms of a major depressive episode.
Difference between Bipolar depression and Other Depressive Disorders
The depression in bipolar must meet the criteria of a major depressive episode. Other depressive disorders include dysthymia, which is less severe than major depression. Dysthymia is characterized by chronic feelings of sadness, low self-esteem and negativity occurring almost every day for at period of at least two years (one year in children and teens). Other symptoms include poor appetite or overeating, sleeping too much or not enough, low energy, poor concentration and difficulty making everyday decisions.
Risks of bipolar depression
Individuals with bipolar disorders experience a sharp contrast between periods of feeling very good and very depressed. This contrast can leave them vulnerable to certain risk factors. In bipolar I disorder in particular, approximately 10 percent to 15 percent of individuals successfully commit suicide, usually while in a depressive episode. Both bipolar I and II individuals tend to be at risk for substance abuse problems, as well, which can lead to additional health or psychological problems.
References
- "Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision", American Psychiatric Association; 2000
- Journal of the American Medical Association: Cross-National Epidemiology of Major Depression and Bipolar Disorder
