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.