DIFFERENTIAL RESTING QUANTITATIVE ELECTROENCEPHALOGRAPHIC ALPHA-PATTERN IN WOMEN WITH ENVIRONMENTAL CHEMICAL INTOLERANCE, DEPRESSIVES, AND NORMALS

Background: Previous research suggests that a subset of individuals wi th intolerance to low levels of environmental chemicals have increased levels of premorbid and/or comorbid psychiatric disorders such as dep ression, anxiety, and somatization. The purpose of this study was to e valuate the psychological profiles and quantitative electroencephalogr aphic (qEEG) profiles at baseline of women with and without chemical i ntolerance (CI). Methods: Participants were middle-aged women who repo rted illness from the odor of common chemicals (CI, n = 14), depressiv es without such intolerances (D, n = 10), and normal controls (N, n = 11). They completed a set of psychological scales and underwent two se parate qEEG recording laboratory sessions spaced 1 week apart, at the same time of day for each subject. Results: CI were similar to D with increased lifetime histories of physician-diagnosed depression (71% vs . 100%), Symptom Checklist 90 (revised) (SCL-90-R) somatization scores , Barsky Somatic Symptom Amplification, and perceived life stressfulne ss, although D had more distress than either CI or N on several other SCL-90-R subscales. CI scored significantly higher on the McLean Limbi c Symptom Checklist somatic symptom subscale than did either D or N. O n qEEG, CI exhibited significantly greater overall resting absolute al pha activity with eyes closed, especially at the parietal midline site (Pz), and increased (sensitized) frontal alpha from session 1 to 2, i n contrast with the D and N groups. D showed right frontal asymmetry i n both sessions, in comparison with CI. Conclusions: The data indicate that CI with affective distress diverge from both D without chemical intolerance and N in qEEG alpha patterns at resting baseline. Although CI descriptively resemble D with increased psychological distress, th e CI's greater alpha suggests the possibility of a) central nervous sy stem hypo-, not hyper-, activation; and/or b) an overlap with EEG alph a patterns of persons with positive family histories of alcoholism. Pu blished 1998 Society of Biological Psychiatry.