Wikipedia [via]:

Burnout is a psychological term for the experience of long-term exhaustion and diminished interest (depersonalisation or cynicism), usually in the work context. It is also used as an English slang term to mean exhaustion. Burnout is often construed as the result of a period of expending too much effort at work while having too little recovery, but it is sometimes argued that workers with particular personality traits (especially neuroticism) are more prone to experiencing burnout.

Neuroticism is a fundamental personality trait in the study of psychology. It can be defined as an enduring tendency to experience negative emotional states. Individuals who score high on neuroticism are more likely than the average to experience such feelings as anxiety, anger, guilt, and depression (Matthews & Deary, 1998). They respond more poorly to environmental stress, and are more likely to interpret ordinary situations as threatening, and minor frustrations as hopelessly difficult. They are often self-conscious and shy, and they may have trouble controlling urges and delaying gratification.

Burnout is a common syndrome in volunteer organisations, for example open-source software development teams, and suggests that the cause of burnout is long-term economic instability rather than stress. Some reports indicate that burnout is project specific, so an individual may be unable to work in one context, but fully functional in another. Anecdotal evidence suggests a treatment for burnout, based on changing the economic model governing the work in question. For example, the switch from volunteer to paid work can apparently cure burnout.

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