Bipolar disorder, also known as manic-depressive illness, is a mental health condition characterized by extreme and unpredictable mood swings. These mood swings can vary from manic episodes, which involve elevated or irritable moods, increased energy, decreased need for sleep, and impulsive behaviour, to depressive episodes, which involve low mood, feelings of hopelessness or worthlessness, changes in appetite and sleep, and difficulty concentrating. The severity and frequency of these mood episodes can vary, and some individuals may experience periods of stability between episodes.