A CONTROLLED COMPARISON OF MULTIPLE CHEMICAL SENSITIVITIES AND CHRONIC FATIGUE SYNDROME

The present study had two objectives: 1) to determine the characterist ics that differentiated subjects with multiple chemical sensitivities (MCS), chemical sensitivities (CS), and chronic fatigue syndrome (CFS) ; and 2) to evaluate the psychiatric and neuropsychological complaints of these groups relative to normal controls. A cross-sectional compar ison was made of the following groups matched for age, sex, and educat ion: 1) patients whose sensitivities to multiple low level chemical ex posures began with a defined exposure (MCS; N = 23); 2) patients with sensitivities to multiple chemicals without a clear date of onset (CS; N = 13); 3) patients meeting CDC criteria for Chronic Fatigue Syndrom e (CFS; N = 18); and 4) normal controls (N = 18). Subjects with sensit ivities to chemicals (MCS and CS) reported significantly more lifestyl e changes due to chemical sensitivities and significantly more chemica l substances that made them ill compared with chronic fatigue and norm al controls. MCS, CS, and CFS patients had significantly higher rates of current psychiatric disorders than normal controls and reported sig nificantly more physical symptoms with no medical explanation. Seventy -four percent of MCS and 61% of CFS did not qualify for any current Ax is I psychiatric diagnosis. Chemically sensitive subjects without a de fined date of onset (CS) had the highest rate of Axis I psychiatric di sorders (69%). On the MMPI-2, 44% of MCS, 42% of CS, 53% of CFS, and n one of the controls achieved clinically significant elevations on scal es associated with somatoform disorders. With the exception of one com plex test of visual memory, no significant differences were noted amon g the groups on tests of neuropsychological function. Standardized mea sures of psychiatric and neuropsychological function did not different iate subjects with sensitivities to chemicals from those with chronic fatigue. Subjects with sensitivities to chemicals and no clear date of onset had the highest rate of psychiatric morbidity. Standardized neu ropsychological tests did not substantiate the cognitive impairment re ported symptomatically. Cognitive deficits may become apparent under c ontrolled exposure conditions.