Chronic fatigue in historical perspective.

Chronic fatigue as a presenting complaint, in the absence of other evident organic illness, was seldom reported historically before the second half of the 19th century. Its first eruption was the so-called 'bed cases' or 'sofa cases' among middle-class females in the period from 1860 to about 1910. 'Neurasthenia' does not necessarily represent an early forerunner of chronic fatigue. Many patients receiving that diagnosis did not complain of fatigue. Others with functional fatigue did not receive the diagnosis 'neurasthenia'. Both medical-anecdotal and quantitative sources make it clear that by the time of the First World War, chronic fatigue was a common complaint in Europe and North America. Medical concepts of chronic fatigue since the 1930s have run along four separate lines: (1) 'postinfectious neuromyasthenia', going back to an atypical 'poliomyelitis' epidemic in 1934; (2) 'chronic Epstein-Barr virus' infection, an illness attribution that increased in frequency after the discovery in 1968 that this virus caused mononucleosis; (3) 'myalgic encephalomyelitis', dating from an epidemic at the Royal Free Hospital in London in 1955; and (4) 'fibrositis', or 'fibromyalgia', used as a rheumatological description since the turn of the century. Recently, these four separate paths have tended to converge into the diagnosis of 'chronic fatigue syndrome'.