Bipolar disorder

Bipolar disorder (BD), previously known as manic depression, is a mental disorder characterized by periods of depression and abnormally elevated mood, lasting 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 and reckless decisions. 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. People with BD are at 11.7 times greater risk of dying by suicide than the general population. Approximately 34% attempt suicide during their lifetime. Among adolescents with BD, 78% engaged in self-harm. The mechanisms of this mood disorder are not clearly understood, although some studies suggest areas for future clinical research. Structural and functional MRI studies have shown differences in brain regions in BD, such as regions involved in perceiving risk-reward and regulating emotions. A systematic review and meta-analysis by Murri and others found that cortisol levels are "associated with the manic phase" of BD. Likewise, various other studies support an important role for hypothalamic-pituitary-adrenal axis (HPA axis). Risk for BD is thought to be influenced by genetics, environment, and ADHD. In one respect (heritability), genetic factors may account for up to 70–90% of the risk of developing BD. In another respect (concordance rate), identical twins both have bipolar disorder (or both do not) at a rate of ~40%, in contrast to dizygotic twins' ~5%. Environmental risks include a history of child abuse and long-term stress. A meta-analysis and a separate critical literature review have found worse prognosis and earlier onset of BD in people with childhood maltreatment and "early...