Odor aversion of multiple chemical sensitivities: recommendation for a name change and description of successful behavioral medicine treatment.

Patients with odor-triggered symptoms, meeting the case definition of multiple chemical sensitivities (MCS), continue to be seen in our institution and other health science centers [Amundsen, Mayo Clinic Dept. Intern. Med. Newslett. 9(1) (1986)]. The term MCS, unfortunately, feeds the thesis that symptoms are allergic-immune system in origin, a theory that has not withstood scientific scrutiny [American College of Physicians, Ann. Intern. Med. 111, 168-178 (1989); Terr, Ann. Intern. Med. 119, 163-164 (1993)]. It has been proposed that some of these cases may be examples of classical (Pavlovian) conditioning: many MCS patients meet diagnostic criteria for psychiatric illnesses, especially mood, anxiety, and somatoform disorders. Attention is turning to the complex relationship between olfactory stimulation, memory, and mood (psyche) in an attempt to understand why some individuals develop odor aversion symptoms and how to best manage these, frequently, severely disabled patients. Two subjects with typical odor-triggered symptoms have been treated, using behavioral medicine techniques, with marked improvement in both cases. The term "odor aversion" is proposed rather than MCS to describe patients with these symptoms.