CLINICALLY RELEVANT EEG STUDIES AND PSYCHOPHYSIOLOGICAL FINDINGS - POSSIBLE NEURAL MECHANISMS FOR MULTIPLE CHEMICAL-SENSITIVITY

This paper addresses the evidence for the face, construct, and criteri on-related validity of the olfactory-limbic/neural sensitization model for multiple chemical sensitivity (MCS). MCS is a poorly-understood, controversial condition in which low levels of environmental chemicals are reported to trigger disabling levels of illness in certain indivi duals. Neural sensitization processes could generate an endogenous amp lification of responsivity to exogenous substances, thereby providing a plausible explanation for the apparent lack of a classical toxicolog ical dose-response relationship in MCS. Convergent data from both surv ey and psychophysiological studies of MCS patients and of persons from the community without MCS, but who report elevated frequency of illne ss from chemical odors (cacosmics), support the involvement of the lim bic system and the sensitizability of cacosmics, as predicted by the m odel. Recent studies show that cacosmics do sensitize their heart rate , blood pressure, and plasma B-endorphin responses to repeated exposur es to a novel laboratory procedure involving dietary manipulations ove r time, Cacosmia may represent a pathological form of neural plasticit y. Taken together, the model and the available evidence suggest the ne ed for more intensive investigation of MCS from the standpoint of poss ible neurobiological mechanisms affecting cognitive, emotional, and so matic functions.