More than 2 million American adults, or about 1 percent of the population age 18 and older in any given year, have bipolar disorder. Bipolar disorder typically develops in late adolescence or early adulthood. However, some people have their first symptoms during childhood, and some develop them late in life. It is often not recognized as an illness, and people may suffer for years before it is properly diagnosed and treated. Like diabetes or heart disease, bipolar disorder is a long-term illness that must be carefully managed throughout a person's life.
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.
It appears likely that many different genes act together, and in combination with other factors of the person or the person's environment, to cause bipolar disorder. Finding these genes, each of which contributes only a small amount toward the vulnerability to bipolar disorder, has been extremely difficult. But scientists expect that the advanced research tools now being used will lead to these discoveries and to new and better treatments for bipolar disorder.
Brain-imaging studies are helping scientists learn what goes wrong in the brain to produce bipolar disorder and other mental illnesses. New brain-imaging techniques allow researchers to take pictures of the living brain at work, to examine its structure and activity, without the need for surgery or other invasive procedures. These techniques include magnetic resonance imaging (MRI), positron emission tomography (PET), and functional magnetic resonance imaging (fMRI). There is evidence from imaging studies that the brains of people with bipolar disorder may differ from the brains of healthy individuals. As the differences are more clearly identified and defined through research, scientists will gain a better understanding of the underlying causes of the illness, and eventually may be able to predict which types of treatment will work most effectively.
In most cases, bipolar disorder is much better controlled if treatment is continuous than if it is on and off. But even when there are no breaks in treatment, mood changes can occur and should be reported immediately to your doctor. The doctor may be able to prevent a full-blown episode by making adjustments to the treatment plan. Working closely with the doctor and communicating openly about treatment concerns and options can make a difference in treatment effectiveness.
In addition, keeping a chart of daily mood symptoms, treatments, sleep patterns, and life events may help people with bipolar disorder and their families to better understand the illness. This chart also can help the doctor track and treat the illness most effectively.
As an addition to medication, psychosocial treatments—including certain forms of psychotherapy (or "talk" therapy)—are helpful in providing support, education, and guidance to people with bipolar disorder and their families. Studies have shown that psychosocial interventions can lead to increased mood stability, fewer hospitalizations, and improved functioning in several areas. A licensed psychologist, social worker, or counselor typically provides these therapies and often works together with the psychiatrist to monitor a patient's progress. The number, frequency, and type of sessions should be based on the treatment needs of each person.
Psychosocial interventions commonly used for bipolar disorder are cognitive behavioral therapy, psychoeducation, family therapy, and a newer technique, interpersonal and social rhythm therapy. NIMH researchers are studying how these interventions compare to one another when added to medication treatment for bipolar disorder.