It was considered to be one of the "factors influencing health status and contact with health services" and "should not be used" for "primary mortality coding". It was also considered one of the "problems related to life-management difficulty". The condition is further defined as being a "state of vital exhaustion," which historically had been called neurasthenia.The ICD-10 also contained a medical condition category of "F43.8 Other reactions to severe stress. "In 2010 the Swedish Board of Health and Welfare added “exhaustion disorder” (ED; F43.8A) to the Swedish version of the ICD-10, the ICD-10-SE, representing what is typically called "burnout" in English. (See also sv:Utmattningssyndrom). Swedish sufferers of severe burnout had earlier been treated as having neurasthenia.The ICD-10-SE defined exhaustion disorder as consisting of:

A. Physical and mental symptoms of exhaustion during at least two weeks. The symptoms have developed in response to one or more identifiable stressors present for at least six months. B. The clinical picture is dominated by markedly reduced mental energy, as manifested by reduced initiative, lack of endurance, or increased time needed for recovery after mental effort. C. At least four of the following symptoms have been present, nearly every day, during the same 2-week period:

Concentration difficulties or impaired memory
Markedly reduced capacity to tolerate demands or to work under time pressure
Emotional instability or irritability
Sleep disturbance
Marked fatigability or physical weakness
Physical symptoms such as aches and pains, palpitations, gastrointestinal problems, vertigo or increased sensitivity to soundD. The symptoms cause clinically significant distress or impairment in occupational, social or other important respects.
According to the World Health Organization (WHO), occupational burnout is a syndrome resulting from chronic work-related stress, with symptoms characterized by "feelings of energy depletion or exhaustion; increased mental distance from one’s job, or feelings of negativism or cynicism related to ones job; and reduced professional efficacy". While burnout may influence health and can be a reason for people contacting health services, it is not itself classified by the WHO as a medical condition or mental disorder. WHO additional states that "Burn-out refers specifically to phenomena in the occupational context and should not be applied to describe experiences in other areas of life." History
According to Wolfgang Kaskcha, "Burnout as a phenomenon has probably existed at all times and in all cultures." He notes that the condition is described in the Book of Exodus. Gordon Parker believes the ancient European concept of acedia refers to burnout, and not depression as many others believe.It has been suggested that the first printed use of the term "burnout" in English was in one of Shakespeares sonnets in 1599, referring to a womans love burning out. The sonnet in question is one of Shakespeares most famous. In 1869, New York neurologist George Beard used the term "neurasthenia" to describe a very broad condition caused by the exhaustion of the nervous system, which was thought to be particularly found in "civilized, intellectual communities." The concept soon became popular, and many in the United States believed themselves to have it. Some came to call it "Americanitis".