The World Health Organization now recognizes work "burnout" as an occupational phenomenon. The syndrome is included in the agency's handbook of medical diagnoses, which guides health professionals around the world.

Symptoms of burnout includes feelings of exhaustion, cynicism about one's job, and difficulty doing the job successfully. The WHO stressed that "burnout" is not classified as a medical condition.

Working too hard is now a recognized as an occupational phenomenon, according to the World Health Organization (WHO). The agency, which guides many health providers and organizations, now includes "burnout" in its International Classification of Diseases Handbook.

The agency described "burnout" as a syndrome resulting from "chronic workplace stress that has not been successfully managed."

According to the WHO, doctors can issue a diagnosis of burnout if a patient exhibits three symptoms: feeling depleted of energy or exhausted; feeling mentally distanced from or cynical about one's job; and problems getting one's job done successfully. The WHO notes that burnout is to be used specifically "in the occupational context" and that it "should not be applied to describe experiences in other areas of life."

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The agency said it plans to develop "evidence-based guidelines on mental well-being in the workplace."

Burnout as a psychological term was first described in the mid-1970s, BuzzFeed reported, when psychologist Herbert Freudenberger used it to describe cases of "physical or mental collapse caused by overwork or stress." Freudenberger ascribed the condition to "helping" professions such as nurses and doctors.

But today, many types of people can suffer from burnout, "from stressed-out careerists and celebrities to overworked employees and homemakers," according to the National Institutes of Health. Last year, a Gallup survey found nearly 1 in 4 employees feels burned out always or often, with another 44 percent saying they feel burned out "sometimes."

Correction: This story has been updated to reflect that WHO does not list work burnout as a medical diagnosis.