POSSIBLE TIME-DEPENDENT SENSITIZATION TO XENOBIOTICS - SELF-REPORTED ILLNESS FROM CHEMICAL ODORS, FOODS, AND OPIATE DRUGS IN AN OLDER ADULT-POPULATION

The present paper summarizes key features of time-dependent sensitizat ion (TDS) in neuropharmacology (progressive amplification of behaviora l, neuronal, endocrine, and/or immune responses to repeated intermitte nt exposures to an environmental agent or cross-sensitizing agents) as a possible model for cacosmia (subjective sense of feeling ill from l ow levels of environmental chemical odors) in nonindustrial and indust rial populations; and extends previous cacosmia research in nonpatient populations to an elderly sample. This study examined the symptom and psychological profiles of 263 older adults (aged 60-90 y, 71% women, 29% men); 57% reported that at least one chemical and 17% reported tha t at least four of five chemicals (pesticide, automobile exhaust, pain t, new carpet, perfume) made them feel ill. Cacosmia ratings correlate d weakly and negatively with age (r = - 0.19, p = .001) over the whole sample. Cacosmia correlated significantly with self-reported illness from foods that may mobilize or generate opioid peptides (wheat, dairy , eggs) (r = 0.32, p < .0001) and with illness from opiate drugs (r = 0.23, p < .0001). When the sample was divided into four cells on the b asis of above- versus below-median total chemical-induced illness scor e (CI) and total food-induced illness score (FI), the high CI and high FI, high CI only, and high FI only groups had more frequent indigesti on, and the high CI group had more frequent difficulty concentrating t han the groups below median for illness from both chemicals and foods (NOILL), even after co-varying for age and anxiety. The most cacosmic subjects noted higher prevalence of physician-diagnosed allergies and irritable bowel than did noncacosmic subjects. In contrast with previo us young adult cohort studies, the older illness groups did not differ with regard to sex distribution, depression, shyness, or repressive d efensiveness. When considered with prior surveys of young adults, the present findings are consistent with the presence of previously establ ished, time-dependent sensitization to multiple xenobiotic agents in s usceptible individuals for whom psychological variables do not explain the symptom of cacosmia. If cacosmia is a symptom of TDS, then the ne uropharmacology literature suggests the possibility of excitatory amin o acid, hypothalamic-pituitary-adrenal axis, dopaminergic, and/or opio id involvement. Prospective studies with objective measures testing th e possible induction of TDS to specific chemicals are indicated.