5.7 million Americans or 2.6 percent of the population are affected by bipolar disorder, but their experiences are not exactly the same. Regarding bipolar disorder, there are four distinct types that help mental health care providers identify and treat patients.
Bipolar I disorder
The one and only criterion for a diagnosis of Bipolar I disorder is having experienced at least one full manic episode. Manic episodes last at least one week or require hospitalization, and cause significant impairment in functioning. Mania is characterized by a dramatic increase in energy and a significantly reduced need for sleep. There may be grandiosity, aggressive behavior and even a break from reality (psychosis). The manic episode may be preceded or followed by major depressive episodes. However, some people with Bipolar I disorder never experience a depressive episode.
Bipolar II disorder
There has been at least one major depressive episode lasting at least two weeks and at least one episode in which abnormally elevated mood and increased energy or irritation are experienced for at least four days (hypomania), but never at the level of the full manic episode that is characteristic for Bipolar I disorder. Major depressive episodes or the unpredictable changes in mood and behavior cause distress or difficulty in multiple areas of your life.
At least two years — or one year in children and teenagers — of numerous periods of hypomanic symptoms alternating with periods of depression. During that time, symptoms occur at least half the time and never go away for more than two months. Mood symptoms don’t meet full criteria of major depression or hypomania, and cause significant distress in important areas of your life.
These include, for example, bipolar and related disorder due to another medical condition, such as Cushing's disease, multiple sclerosis or stroke. Another type is called substance and medication-induced bipolar and related disorder.
Research suggests bipolar disorder is 60 percent hereditary, and that it typically appears in adolescence or before the age of 25, but it can also emerge later in life. Biological differences in the brain and an imbalance of chemicals called neurotransmitters and hormones could also contribute. Stressors can act as triggers of an onset, like emotional or physical trauma. Bipolar I disorder is a life-long condition that requires use of medication. Cognitive therapy can assist with early identification and management of symptoms that appear to be chronic or signal onset of a major mood episode. Family members of a person struggling with bipolar disorder often benefit from therapy as well, both in a group and individual settings.