Bipolar disorder, also known as manic depression, causes extreme mood swings characterized by manic highs and depressive lows. Its symptoms—extreme sadness, feelings of worthlessness, loss of interest in activities, anger, racing thoughts, and the feeling of being out of control—can be extremely disruptive to one's life. Extreme manic or depressive episodes may also lead to psychotic symptoms such as delusions and hallucinations. The onset of symptoms generally occurs in late adolescence or young adulthood, yet bipolar disorder can be a long-lasting and devastating disorder. It often leads to risky behavior during manic episodes, and during depressive episodes, the risk for suicide is very high. Genetic factors contribute substantially to the likelihood of developing bipolar disorder, but environmental factors are also implicated in its origin. About 5.7 million people in the United States have bipolar disorder, representing about 2% of the population. Though difficult to overcome, bipolar disorder can be treated and managed. It is often treated with mood stabilizer medications or other psychiatric drugs. Psychotherapy can also be extremely effective in helping people cope with and manage its symptoms.