INCREASED LIMBIC SYSTEM SYMPTOMATOLOGY AND SENSITIZABILITY OF YOUNG-ADULTS WITH CHEMICAL AND NOISE SENSITIVITIES

We previously hypothesized that individual differences in (a) limbic s ystem reactivity and (b) central nervous system sensitizability underl ie vulnerability to environmental stimuli, not only in the controversi al clinical condition multiple chemical sensitivity (MCS), but also in the general population. Earlier research has shown overlaps in the ch aracteristics of persons who report noise and air pollutant sensitivit ies. This study assessed questionnaire responses of 897 young adult co llege students who reported high versus low frequency of illness from several environmental chemical odors and concomitantly high versus low sensitivity to environmental noise. Subjects who reported increased r ates of illness from chemical odors with or without noise sensitivity scored significantly higher (P < 0.0001) on a measure of limbic system symptomatology derived from ictal sensory, somatic, mnemonic, and beh avioral manifestations of temporal lobe epilepsy, The group rating hig h both for illness from chemicals and for noise sensitivity had charac teristics predictive of heightened sensitizability from the animal res earch on time-dependent sensitization (progressive response amplificat ion to repeated, intermittent stimuli over time): i.e., higher female to male ratio (gender risk factor), increased rates of drug abuse prob lems in blood relatives (genetic risk factor), trait shyness (hyperrea ctivity to novelty), and increased carbohydrate craving, Despite the i ncreased family histories of drug abuse and levels of personal anxiety and depression, the chemical- and noise-sensitive group reported the lowest rates of current smoking or personal drug abuse problems and th e highest frequency of illness from drinking a small amount of alcohol . Taken together, the findings suggest that limbic system dysfunction associates more with chemical than with noise sensitivity; that indivi duals with both chemical and noise sensitivity may be the most sensiti zable subset of the population for prospective studies, and that, in t heir substance use patterns, young adults with both chemical and noise sensitivity are more similar to MCS patients than are their peers wit h chemical or noise sensitivity alone. (C) 1995 Academic Press, Inc.