, 1999; Fukuda, 1994). Depression is a common symptom reported by CFS patients. Studies have indicated that the depression described may be due to CFS rather than a psychiatric disorder (Evengard et al.). CFS patients have reported that their symptoms seriously affect all levels of functioning. Everyday tasks were described as requiring excessive effort. Also reported were sleep disturbances and fatigue resulting in a decreased quality of life (Wagner-Raphael, Jason & Ferrari, 1999).
No pathognomonic signs or diagnostic tests for CFS have been validated in scientific studies and no definitive treatment exists. Many illnesses however, are characterized by chronic fatigue as a major symptom, one of which is chronic depression. Biochemical imbalances have been identified as potential causal factors in diseases such as depression and long-term autoimmune diseases (Gimenez, Cash, Laing & Douglas, 1999; Wilson et al., 1996). This raises the possibility that an imbalance may lead to the identification of a CFS causing mechanism such as C-1 esterase inhibitor.
C-1 esterase inhibitor deficiency has been identified as resulting in hereditary and acquired angio-neurotic edema (HANE, AANE). C-1 esterase inhibitor deficiency results in unchecked classical complement