[Expert assessment of chronic fatigue syndrome]

The Chronic-Fatigue-Syndrome (CFS) has been first described in 1988 and has been also in Germany recently more frequently diagnosed. It is similar to a lot of other terms, especially to "neurasthenia", which has been introduced 1869 from Beard and is now again content of ICD-10. CFS is defined by primary and secondary criteria, which are however largely subjective. There are no objective signs. It is unknown if this syndrome represents a disease entity of its own. The explanation is either exclusive organic based on immunological and virological findings or exclusive psychogenic as a special form of anxiety psychosis. Possibly are both factors involved as part of "psycho-neuro-immunology". CFS is increased subject of medical certification. It has been tried to give a practical guidance to the assessment of CFS.