Bipolar disorder (BD), previously known as manic depression, is a mental disorder characterized by periods of depression and of abnormally elevated mood that each last from days to weeks, and in some cases months. If the elevated mood is severe or associated with psychosis, it is called mania; if it does not significantly affect functioning, it is called hypomania. During mania, an individual behaves or feels abnormally energetic, happy, or irritable, and often makes impulsive decisions with little regard for the consequences. There is usually sleep disturbance during manic phases. During periods of depression, the individual may experience crying, have a negative outlook, and demonstrate poor eye contact. An estimated 15–20% of those with BD died by suicide, with about one-third attempting suicide in their lifetime. Among those with BD, 40–50% overall and 78% of adolescents engaged in self-harm.