Natural history and prognosis
Onset is usually in the mid-20s but can occur at any time. Outcome varies by setting and severity, the median episode duration ranges from 4 to 12 months with 10% having an unremitting course an many others experiencing fluctuating degrees of symtoms. At least 50% of people will experience a subsequent relapse, increasing to 90% after the third episode, with a median of four lifetime episodes. Poorer outcome is associated with earlier age of onset, episode number, duration,severity and treatment resistance, psychosis,cognitive impairment. Physical and psychiatric co-morbidity and ongoing social adversity. At least 10% of patients. especially after only onset, are subsequently found to have bipolar disorder. Eventual death through suicide is increased fourfold to 2% in community samples, rising to 9% in the most severely ill. Depression increases the morbidity mortality in a range of physical illnesses.