Do you go through intense mood swings? Do you feel very happy and energized some days, and very sad and depressed on other days? Do these moods last for a week or more? Do your mood changes make it hard to sleep, stay focused, or go to work?
Some people with these more severe symptoms have bipolar disorder, a serious mental illness. Also known as manic-depressive illness, it is a brain disorder that causes unusual shifts in mood, energy, activity levels, and the ability to carry out day-to-day tasks. They are different from the normal ups and downs that everyone goes through from time to time. Bipolar disorder symptoms can result in damaged relationships, poor job or school performance, and even suicide. But bipolar disorder can be treated, and people with this illness can lead full and productive lives.
Source: National Institute of Mental Health (NIMH)