CHRONIC FATIGUE SYNDROME .1. ETIOLOGY AND PATHOGENESIS

Chronic fatigue syndrome (CFS) is a disorder of unknown etiology chara cterized by debilitating fatigue and other somatic and neuropsychiatri c symptoms. A range of heterogeneous clinical and laboratory findings have been reported in patients with CFS. Various theories have been pr oposed to explain the underlying pathophysiologic processes but none h as been proved. Research findings of immunologic dysfunction and neuro endocrine changes suggest the possible dysregulation of interactions b etween the nervous system and the immune system. Without a clear under standing of its etiopathogenesis, CFS has no definitive treatment. Man agement approaches have been necessarily speculative, and they have ev olved separately in a number of medical and nonmedical disciplines. Th e results of several controlled treatment studies have been inconclusi ve. An accurate case definition identifying homogeneous subtypes of CF S is needed. The integration of medical and psychologic treatment moda lities and the use of both biologic and psychologic markers to evaluat e treatment response will enhance future treatment strategies.