Introduction:

Bipolar disorder, formerly called manic-depression, is characterized by moods that swing between two opposite poles:

• Periods of mania with exaggerated euphoria, irritability, or both
• Episodes of depression

Although chemical imbalances in the brain are a key component of bipolar disorder, it is a complex condition that involves genetic, environmental, and other factors.

Bipolar Disorder Categories

Bipolar disorder is classified according to the pattern and severity of the symptoms as bipolar disorder I, bipolar disorder II, or cyclothymic disorder. Patients with one type may develop another. Nevertheless, they are distinct enough to merit separate classifications. Some doctors believe these conditions are actually separate disorders with different biologic factors that account for their differences.

Bipolar Disorder I. Bipolar disorder I is characterized by at least one manic episode or mixed episode (symptoms of both mania and depression occurring simultaneously), and one or more depressive episodes, that lasts for at least 7 days. In most cases, manic episodes precede or follow depressive episodes in a regular pattern. Episodes are more acute and severe than in the other two categories.

Without treatment, patients average four episodes of dysregulated mood each year. With mania, either euphoria or irritability may mark the phase. In addition, there are significant negative effects (such as sexual recklessness, excessive and impulsive shopping, and sudden traveling) on a patient's social life, performance at work, or both. Untreated mania lasts at least a week, and it can last for months. Typically, depressive episodes tend to last 6 - 12 months, if left untreated.

Bipolar Disorder II. Bipolar disorder II is characterized by episodes of predominantly major depressive symptoms, with occasional episodes of hypomania, which last for at least 4 days. Hypomania is similar to mania, but the symptoms (typically euphoria) are less severe and do not last as long.

Patients do not experience manic or mixed episodes, and most return to fully functional levels between episodes. However, bipolar II patients have a more chronic course, significantly more depressive episodes, and shorter periods of being well between episodes than patients with type I have. It is highly associated with the risk for suicide.

Cyclothymic Disorder. While cyclothymic disorder is not as severe as either bipolar disorder II or I, the condition is more chronic. Hypomanic symptoms tend toward irritability as compared to the more euphoric symptoms of bipolar II.

The disorder lasts at least 2 years, with single episodes persisting for more than 2 months. Cyclothymic disorder may be a precursor to full-blown bipolar disorder in some people or it may continue as a low-grade chronic condition.

Bipolar Disorder Not Otherwise Specified (NOS). Bipolar disorder that does not meet one the above criteria is classified as Bipolar Disorder NOS.

Bipolar Disorder with Rapid Cycling. Bipolar disorder with rapid cycling involves four or more manic, hypomanic, or depressive episodes within a 12-month period. Mood swings can shift rapidly from mania to depression over the course of several days or hours. Rapid cycling can occur with any type of bipolar disorder. The condition is usually temporary.