Multiple sclerosis (MS) is a chronic-inflammatory autoimmune central nervous system disorder and a leading cause of neurological disability in younger adults in Western countries. Besides "classic" neurological symptoms both depressivity and fatigue are among the most frequent symptoms in MS, affecting up to 90% of patients at onset or during the course of the disease. Neither are the psychological and immunological backgrounds of both well understood, nor are there numerous controlled therapeutic trials which would offer convincing treatment options for fatigue and depressivity in MS.