It's a condition that usually starts in early adulthood, consists of episodes of depression and mania in varying combinations. Episodes are recurrent. It's estimated that patients not on preventive treatment will experience an average of nine to ten episodes in their lifetime. Episodes last an average of one and a half to four months, though some people are ill for years at a time. Although psychological stress is prominent in early episodes, later ones tend to have a life of their own, less linked to stress.
Episodes tend to get more frequent with age.
Current thinking favors the notion that episodes actually cause changes in the brain that prepare the way for later episodes and progressive intensity of illness. Mania and depression, it should be remembered, are disruptive events. Jobs are lost, marriages severely tried, social relations undermined. Some 10 percent of patients eventually successfully commit suicide. There is a small risk of some degree of kidney impairment.