Several clinical and epidemiological studies conducted in the United States and in the United Kingdom have investigated the occurrence of MCS in military personnel deployed to the Persian Gulf during the 1990s.
Gulf War veterans have an increased rate of multiple-symptom conditions compared to military personnel deployed to other conflicts, and although it is unexplained, Gulf War syndrome is not considered distinct from other medically unexplained syndromes observed in civilian populations, including MCS [REF].