Bipolar disorder, also known as manic-depressive illness, is a brain disorder that causes unusual shifts in mood, energy, activity levels, and the ability to carry out day-to-day tasks.
There are four basic types of bipolar disorder; all of them involve clear changes in mood, energy, and activity levels. These moods range from periods of extremely “up,” elated, and energized behavior (known as manic episodes) to very sad, “down,” or hopeless periods (known as depressive episodes). Less severe manic periods are known as hypomanic episodes.
- Bipolar I Disorder— defined by manic episodes that last at least 7 days, or by manic symptoms that are so severe that the person needs immediate hospital care. Usually, depressive episodes occur as well, typically lasting at least 2 weeks. Episodes of depression with mixed features (having depression and manic symptoms at the same time) are also possible.
- Bipolar II Disorder— defined by a pattern of depressive episodes and hypo manic episodes, but not the full-blown manic episodes described above.
- Cyclothymic Disorder (also called cyclothymia)— defined by numerous periods of hypo manic symptoms as well numerous periods of depressive symptoms lasting for at least 2 years (1 year in children and adolescents). However, the symptoms do not meet the diagnostic requirements for a hypomanic episode and a depressive episode.
- Other Specified and Unspecified Bipolar and Related Disorders— defined by bipolar disorder symptoms that do not match the three categories listed above.
Signs and Symptoms
People with bipolar disorder experience periods of unusually intense emotion, changes in sleep patterns and activity levels, and unusual behaviors. These distinct periods are called “mood episodes.” Mood episodes are drastically different from the moods and behaviors that are typical for the person. Extreme changes in energy, activity, and sleep go along with mood episodes.
$$## Table ##$$
Sometimes a mood episode includes symptoms of both manic and depressive symptoms. This is called an episode with mixed features. People experiencing an episode with mixed features may feel very sad, empty, or hopeless, while at the same time feeling extremely energized.
Bipolar disorder can be present even when mood swings are less extreme. For example, some people with bipolar disorder experience hypomania, a less severe form of mania. During a hypo manic episode, an individual may feel very good, be highly productive, and function well. The person may not feel that anything is wrong, but family and friends may recognize the mood swings and/or changes in activity levels as possible bipolar disorder. Without proper treatment, people with hypomania may develop severe mania or depression.
Bipolar Disorder and Other Illnesses
Some bipolar disorder symptoms are similar to other illnesses, which can make it hard for a doctor to make a diagnosis. In addition, many people have bipolar disorder along with another illness such as anxiety disorder, substance abuse, or an eating disorder. People with bipolar disorder are also at higher risk for thyroid disease, migraine headaches, heart disease, diabetes, obesity, and other physical illnesses.
Psychosis: Sometimes, a person with severe episodes of mania or depression also has psychotic symptoms, such as hallucinations or delusions. The psychotic symptoms tend to match the person’s extreme mood. For example:
- Someone having psychotic symptoms during a manic episode may believe she is famous, has a lot of money, or has special powers.
- Someone having psychotic symptoms during a depressive episode may believe he is ruined and penniless, or that he has committed a crime.
As a result, people with bipolar disorder who also have psychotic symptoms are sometimes misdiagnosed with schizophrenia.
Anxiety and ADHD: Anxiety disorders and attention-deficit hyperactivity disorder (ADHD) are often diagnosed among people with bipolar disorder.
Substance Abuse: People with bipolar disorder may also misuse alcohol or drugs, have relationship problems, or perform poorly in school or at work. Family, friends and people experiencing symptoms may not recognize these problems as signs of a major mental illness such as bipolar disorder.
Scientists are studying the possible causes of bipolar disorder. Most agree that there is no single cause. Instead, it is likely that many factors contribute to the illness or increase risk.
Brain Structure and Functioning: Some studies show how the brains of people with bipolar disorder may differ from the brains of healthy people or people with other mental disorders. Learning more about these differences, along with new information from genetic studies, helps scientists better understand bipolar disorder and predict which types of treatment will work most effectively.
Genetics: Some research suggests that people with certain genes are more likely to develop bipolar disorder than others. But genes are not the only risk factor for bipolar disorder. Studies of identical twins have shown that even if one twin develops bipolar disorder, the other twin does not always develop the disorder, despite the fact that identical twins share all of the same genes.
Family History: Bipolar disorder tends to run in families. Children with a parent or sibling who has bipolar disorder are much more likely to develop the illness, compared with children who do not have a family history of the disorder. However, it is important to note that most people with a family history of bipolar disorder will not develop the illness.