Idiopathic environmental intolerances (IEI)/multiple chemical sensitivity (MCS) is characterized by various somatic symptoms which cannot be explained organically, but are attributed to the influences of toxic environmental chemicals in low, usually harmless doses. In the absence of a widely accepted definition of IEI, contradictory aetiological hypotheses and therapeutic suggestions are discussed. Some authors doubt the existence of IEI/MCS as a disease entity of its own. The label IEI does not implicate neither a diagnosis of somatic disease nor that it is caused by an avoidable exposure. Many IEI patients suffer from psychiatric diseases. A majority of them can be diagnosed as somatoform disorders. Consequently, psychiatric therapies could be effective. This review describes the current knowledge about IEI/MCS, outlines a diagnostic algorithm and a psychotherapeutic concept for variants of IEI understood as a somatoform disorder.

Controversy surrounds the origin of symptoms attributed to environmental pollutants or widely used chemicals, and the authors believed that a psychiatric evaluation could advance understanding of this contentious condition. They assessed psychiatric morbidity, somatization, and self-attentiveness in patients seen in their Environmental Clinic. Two hundred ninety-five consecutive patients underwent SCID-I and -II interviews and were investigated with self-rating scales for self-attentiveness and somatization. The authors found a high prevalence of mental disorders (66% had a current SCID diagnosis, and 75% had a lifetime SCID diagnosis) and a low level of self-attentiveness, which was not necessarily associated with psychiatric disease. Among patients visiting an Environmental Clinic, mental disorders were common and needed to be diagnosed and treated by standard interventions. Patients who did not meet diagnostic criteria for a psychiatric disorder had relatively low somatization scores and low private self-attentiveness. These "externalizers" could benefit from an intervention that teaches them to focus on their internal and emotional lives. In these patients, the authors consider low self-attentiveness a major feature that may act as a pathogenic factor for environmental illness.

Multiple chemical sensitivity (MCS) or idiopathic environmental intolerance (IEI) is understood as an acquired disorder with multiple recurrent symptoms that cannot be traced to any well-known medical or psychiatric condition and is associated with diverse environmental influences that are well tolerated by the majority of people. In a prospective study, we investigated 120 consecutive patients admitted a university-based outpatient department for environmental medicine during 1 year. Apart from routine medical examination and special toxicological diagnostic procedures, a structured clinical interview for DSM-IV psychiatric disorders was performed with every patient. At least one psychiatric diagnosis was found in 100 patients. The diagnostic criteria for somatoform disorders were filled by 53 patients. We found lifetime or current affective disorders in 39 patients, anxiety disorders in 29, and substance dependency or abuse in 25. In 16 patients, personality disorders were diagnosed. Nine suffered from psychotic disorders. This is the largest prospective study with standardized psychiatric diagnostic methods concerning psychiatric morbidity and MCS. The data show that many patients with environmental health problems obviously suffer from somatoform disorders but also from other, well-known psychiatric conditions.

Bornschein S, Fo Èrstl H, Zilker T (Technische Universita Èt Mu È nchen, Mu È nchen, Germany). Idiopathic environmental intolerances (formerly multiple chemical sensitivity) psychiatric perspectives. J Intern Med 2001; 250: 309±321.

The influence of nutritional factors on brain metabolism and the course of mental illness are increasingly being addressed in international research. It is a matter of discussion whether dietary habits, e.g., the amount of fish or vegetables, have an effect on the incidence of certain illnesses. Furthermore an optimized or supplemented diet could offer therapeutic possibilities; one example is the role of polyunsaturated fatty acids as an add-on therapy in affective disorders. The limitations of psychopharmacotherapy (drug interactions, side effects, noncompliance) underline the theoretical and practical relevance of nutrition in mental illness, the more so as mentally ill patients (especially when demented, anorectic, depressed, or schizophrenic) are at higher risk of malnutrition anyway. Even if the therapeutic evidence is still limited and the effects may be relatively weak, nutritional assessment and an optimized diet can be recommended for every patient.