Bipolar Disorders are treatable medical illnesses due to abnormalities in brain chemistry and in the structure and/or activity of certain brain circuits. They are usually marked by extreme changes in mood energy and behavior. However, not all cases of bipolar disorder are the same. The disorder(s) used to be called manic depression because in many – but not all – persons with bipolar disorder(s), their mood may alternate between signs and symptoms of mania and depression. Bipolar disorders are sometimes referred to as plural because different people with this diagnosis can react very differently. Furthermore, when people with bipolar disorders take their therapy or treatment as prescribed, they often basically act like all other people. (Much more information about bipolar disorders can be found in our Mental Health Channel, including a list of celebrities and other accomplished notables who have had bipolar disorder or depression, which is also called unipolar depression).