Environ Health Perspect 2002 Aug;110 Suppl 4:669-71
Responses to panic induction procedures in subjects with
multiple chemical sensitivity/idiopathic environmental
intolerance: understanding the relationship with panic
disorder.
Tarlo SM, Poonai N, Binkley K, Antony MM, Swinson RP.
Gage Occupational and Environmental Health Unit,
University of Toronto, Toronto, Ontario, Canada
Idiopathic environmental intolerance (IEI), also
known as multiple chemical sensitivity, is a clinical
description for a cluster of symptoms of unknown
etiology that have been attributed by patients
to multiple environmental exposures when other
medical explanations have been excluded.
Because allergy has not been clearly demonstrated
and current toxicological paradigms for
exposure-symptom relationships do not readily
accommodate IEI, psychogenic theories have
been the focus of a number of investigations.
A significantly higher lifetime prevalence of major
depression, mood disorders, anxiety disorders,
and somatization disorder has been reported
among patients with environmental illness compared
with that in controls. Symptoms often include
anxiety, lightheadedness, impaired mentation,
poor coordination, breathlessness (without
wheezing), tremor, and abdominal discomfort.
Responses to intravenous sodium lactate challenge
or single-breath inhalation of 35% carbon dioxide
versus a similar breath inhalation of clean air
have shown a greater frequency of panic responses
in subjects with IEI than in control subjects,
although such responses did not occur in all
subjects. Preliminary genetic findings suggest an
increased frequency of a common genotype with
panic disorder patients. The panic responses in
a significant proportion of IEI patients opens a
therapeutic window of opportunity. Patients in
whom panic responses may at least be a
contributing factor to their symptoms might be
responsive to intervention with psychotherapy
to enable their desensitization or deconditioning of
responses to odors and other triggers, and/or may
be helped by anxiolytic medications, relaxation
training, and counseling for stress management.