Multiple Chemical Sensitivities: Psychogenic or Toxicodynamic Origins

Abstract

The multiple chemical sensitivity (MCS) phenomenon can cause signi cant dysfunction and symptomatology and presents a difcult challenge for patient management. Central to the MCS debate is whether this phenomenon results from a primary emotional response to perceived chemical exposures or from pathological interactions between chemicals and biological systems. Those who believe the latter argue that toxic interactions result in physiological impairment and that subsequent emotional problems derive from such impairment. Distinguishing between psychogenic (emotional) or a toxicodynamic (chemical toxicity) origin is essential to the medical management of an MCS patient. A psychogenic basis requires treatment with appropriate behavioral therapies; in contrast, a belief in a strictly toxicodynamic etiology argues for avoidance and often precludes treatments that address the psychological responses. Current scienti c evidence strongly suggests that behavioral or psychogenic explanations predominate for reported MCS symptoms. Acceptance of a purely toxic origination (i.e., pathological abnormalities result from a low level chemical exposure) de es known toxicological and medical principles; whereas psychogenic explanations are consistent with these principles. Because symptoms are the end points of many diseases with many causes, both physical and emotional, modern medicine is charged with and expected to consider both when treating MCS patients. The argument can be made that insuf cient information exists about the causal nature of many diseases, and future research may provide support for a strict toxicodynamic cause. However, the practice of medicine must be based upon current knowledge, not future possibilities. Proper care of MCS patients requires identifying the existence of both psychological and organic pathological dysfunction. The rejection of a psychological aspect of the MCS phenomenon and appropriate behavioral treatments is both illogical and detrimental to MCS sufferers.