It if felt that the investigations up to date have not revealed any clear pathological or physiological abnormality attributable to chemical exposure. Given this point of view then, MCS can be defined in terms of beliefs and behaviors. Patients with MCS believe their symptoms result from low-level chemical exposure. There is, however, no clear evidence that symptoms correlate with chemical exposure. The controversy surrounding the cause and treatment of MCS is ideally suited to the application of psychiatry.
Psychiatric diagnoses are largely a group of loosely defined clinical syndromes with a clear cause.
Despite a montage of incompatible ideas about cause, there is some consensus on effective treatment. It may never be known what causes MCS, but that has not stopped clinicians from pushing past controversial and unresolved questions to what treatment actually works. The application of psychiatry is not based on any sound evidence that MCS is a psychiatric illness. If a cause or cure were found, and cause does not necessarily lead to cure, the argument for psychiatric treatment would remain viable and legitimate. Treatments will not be discussed here.