75% Of MCS "Sufferers" Have Comorbid Psychiatric Disorders

Psychol Med 2002 Nov;32(8):1387-94
Psychiatric and somatic disorders and multiple
chemical sensitivity (MCS) in 264 'environmental
patients'.
Bornschein S, Hausteiner C, Zilker T, Forstl H.
Psychiatric Clinic and Department of Toxicology,
I, Medical Clinic, Technical University of
Munich, Germany.

BACKGROUND: An increasing number of
individuals with diverse health complaints are
currently seeking help in the field of environmental
medicine. Multiple chemical sensitivity (MCS)
or idiopathic environmental intolerances (IEI)
is defined as an acquired disorder with multiple
recurrent symptoms associated with environmental
chemicals in low concentrations that are well
tolerated by the majority of people. Their symptoms
are not explained by any known psychiatric
or somatic disorder.

METHOD: Within a 2-year period we
examined 264 of 267 consecutive
patients prospectively presenting to a university
based out-patient department for environmental
medicine. Patients underwent routine medical
examination, toxicological analysis and the
structured clinical interview for DSM-IV
psychiatric disorders (SCID).

RESULTS: Seventy-five per cent of the patients
met DSM-IV criteria for at least one psychiatric
disorder and 35% of all patients suffered from
somatoform disorders. Other frequent diagnoses
were affective and anxiety disorders, and
dependence or substance abuse. In 39%
a psychiatric disorder, in 23% a somatic
condition and in 19% a combination of the two
were considered to provide sufficient
explanation of the symptoms. Toxic chemicals
were regarded as the most probable cause in only
five cases. The suspected diagnosis of MCS/IEI
could not be sustained in the vast majority of cases.

CONCLUSION: This investigation confirms
previous findings that psychiatric morbidity is
high in patients presenting to specialized centres
for environmental medicine. Somatoform
disorders are the leading diagnostic category,
and there is reason to believe that certain
'environmental' or MCS patients form a special
subgroup of somatoform disorders. In most
cases, symptoms can be explained by well-defined
psychiatric and medical conditions other than
MCS, which need specific treatment. Further
studies should focus on provocation testing in order
to find positive criteria for MCS and on therapeutic
approaches that consider psychiatric aspects.