Bipolar Disorder

What Causes Bipolar Disorder?

Scientists are learning about the possible causes of bipolar disorder through several kinds of studies. Most scientists now agree that there is no single cause for bipolar disorder—rather, many factors act together to produce the illness.

Because bipolar disorder tends to run in families, researchers have been searching for specific genes—the microscopic "building blocks" of DNA inside all cells that influence how the body and mind work and grow—passed down through generations that may increase a person's chance of developing the illness. But genes are not the whole story. Studies of identical twins, who share all the same genes, indicate that both genes and other factors play a role in bipolar disorder. If bipolar disorder were caused entirely by genes, then the identical twin of someone with the illness would always develop the illness, and research has shown that this is not the case. But if one twin has bipolar disorder, the other twin is more likely to develop the illness than is another sibling.

Suicide

Some people with bipolar disorder become suicidal. Anyone who is thinking about committing suicide needs immediate attention, preferably from a mental health professional or a physician. Anyone who talks about suicide should be taken seriously. Risk for suicide appears to be higher earlier in the course of the illness. Therefore, recognizing bipolar disorder early and learning how best to manage it may decrease the risk of death by suicide.

What Is the Course of Bipolar Disorder?

Episodes of mania and depression typically recur across the life span. Between episodes, most people with bipolar disorder are free of symptoms, but as many as one-third of people have some residual symptoms. A small percentage of people experience chronic unremitting symptoms despite treatment.

The classic form of the illness, which involves recurrent episodes of mania and depression, is called bipolar I disorder. Some people, however, never develop severe mania but instead experience milder episodes of hypomania that alternate with depression; this form of the illness is called bipolar II disorder. When four or more episodes of illness occur within a 12-month period, a person is said to have rapid-cycling bipolar disorder. Some people experience multiple episodes within a single week, or even within a single day. Rapid cycling tends to develop later in the course of illness and is more common among women than among men.

Editor's Note:

"Race" is sometimes mentioned as a risk factor in the development of certain cancers and a number of other diseases. When you read this in a discussion about an illness, note that the explanation seldom refers to anything biological. Instead, it usually refers to behavior, such as eating habits. The kinds of behavior usually mentioned as risk factors are culturally determined. They are not genetic or biological.