Patients with environmental illness experience a large number of psychological symptoms. The nature of these symptoms and their pathogenesis (toxicogenic versus psychogenic) is controversial. The objective was to (1) characterize the nature of the psychological symptoms according to well-established diagnostic criteria, and (2) to investigate the association between toxicological factors and psychological symptoms.
Toxic burden, somatic morbidity, and psychiatric morbidity were assessed in 309 outpatients with environmental illness and 59 semiconductor industry workers matched for age and gender. Psychiatric disorders were assessed by a structured psychiatric interview (SCID), and distress was assessed by the Symptom-Checklist-90-Revised (SCL-90-R). Routine and specific laboratory tests in blood and urine samples were used to assess chemical exposures.
Overall psychiatric morbidity was significantly higher in patients than in controls according to SCID (75% versus 24%). Somatoform, mood, and anxiety disorders were significantly more frequent in patients with environmental illness. They also revealed marked stress on the SCL-90-R somatization subscale and scored significantly higher than controls on most of the other subscales. Industry workers from the control group tended to have higher urine metal concentrations than environmental illness patients and similar concentrations of solvents in blood.
Our data extend previous findings of high psychiatric morbidity in patients with environmental illness. They do not support the notion of a direct causal link between chemical exposure and the psychological symptoms.
IEI = idiopathic environmental intolerances; EI = environmental illness; SCID = Structured Clinical Interview for DSM-IV; AG = Aktiengesellschaft (corporation); BAT = Biologischer Arbeitsstoff-Toleranzwert (German occupational threshold limit value); SCL-90-R = Symptom Checklist 90-Revised; DSM-IV = Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition; PSDI = positive symptom distress index.
From the Department of Toxicology, II. Med. Clinic (S.B., C.H., T.Z.) and the Department of Psychiatry and Psychotherapy (S.B., C.H., H.F.), Technical University of Munich, Munich, Germany; and Siemens AG, Medical Department, Munich, Germany (F.K.).
Address correspondence and reprint requests to Susanne Bornschein, MD, Department of Toxicology, II. Med. Clinic, Technical University of Munich, Ismaninger Str. 22, D-81675 München, Germany. E-mail: firstname.lastname@example.org
Received for publication July 28, 2004; revision received August 22, 2005.
The study was performed at the Department of Toxicology, II. Med. Clinic, Technical University of Munich, Germany, and the Siemens AG, Otto-Hahn-Ring 6, D-81739 München, Germany.
The study was supported by a grant from the Bavarian State Ministry for State Development and Environmental Affairs.