Depression is a condition associated with sad mood and/or loss of interest in pleasurable activities that used to be pleasurable. Someone who is depressed can have difficulty initiating tasks, may experience loss of appetite or overeating, and even suicidal behavior. Someone with depression may feel sad, empty, hopeless, helpless, guilty, or restless regardless of their life circumstances.
Bipolar disorder, also known as manic-depressive illness, is a complex brain disorder that involves sudden mood shifts from high to low. These dramatic mood swings, known as episodes, are referred to as stages of mania and depression. Bipolar disorder affects over five million Americans.