Bipolar disorder, also known as manic-depression, is a treatable condition that typically causes extreme swings in mood, thought, energy, and behavior. There can often periods of normal mood between episodes. This medical problem is not due to personal weakness or a character flaw.

The mood swings associated with bipolar disorder are different from the average ups and downs experienced by everybody in life and in severe cases can be associated with psychotic symptoms, such as hallucinations, delusions, or thought disorganization. They can result in damaged relationships, poor job or school performance, and even suicide. When treated appropriately, people with this illness can lead full and productive lives.

Bipolar disorder affects an estimated 2.6% of American adults (18 and older). The condition typically develops in late adolescence or early adulthood. However, some people have their first symptoms during childhood, and some develop symptoms late in life. Bipolar disorder is a long-term illness that must be carefully managed by a medical professional throughout a person's life.

The cause of bipolar disorder is unknown, but it tends to run in families. Specific genes may play a role, but it is not caused by one single gene. Additional factors, including stressors at home, work, or school, are believed to be involved in its onset.

People with bipolar disorder are at increased risk for suicide, substance abuse, and high risk behaviors such as reckless driving and sexual promiscuity. Anxiety disorders, such as post-traumatic stress disorder and obsessive-compulsive disorder, tend to occur at a higher rate in people with bipolar disorder.