Bipolar disorder, formerly manic depression, is a mental disorder with periods of depression and periods of elevated mood. The elevated mood is significant and is known as mania or hypomania, depending on its severity, or whether symptoms of psychosis are present. During mania an individual behaves or feels abnormally energetic, happy or irritable. Individuals often make poorly thought out decisions with little regard to the consequences. The need for sleep is usually reduced during manic phases. During periods of depression there may be crying, a negative outlook on life, and poor eye contact with others. The risk of suicide among those with the illness is high at greater than 6 percent over 20 years, while self-harm occurs in 30-40 percent. Other mental health issues such as anxiety disorders and substance use disorder are commonly associated.
The causes are not clearly understood, but both environmental and genetic factors play a role. Many genes of small effect, contribute to risk. Environmental factors include a history of childhood abuse and long-term stress. It is divided into bipolar I disorder if there is at least one manic episode and bipolar II disorder if there are at least one hypomanic episode and one major depressive episode. In those with less severe symptoms of a prolonged duration the condition cyclothymic disorder may be present. If due to drugs or medical problems it is classified separately. Other conditions that may present in a similar manner include attention deficit hyperactivity disorder, personality disorders, schizophrenia and substance use disorder as well as a number of medical conditions. Medical testing is not required for a diagnosis. However, blood tests or medical imaging can be done to rule out other problems.