A new study shows that those suffering from Multiple Chemical Sensitivity have not suffered a higher number of traumatic events in the past than healthy individuals.
The research provides further evidence that Multiple Chemical Sensitivity (MCS), or Idiopathic Environmental Intolerance (IEI) as it is referred to by the authors, is not a psychological illness.
Researchers from the Department of Clinical Psychology at the Central Institute of Mental Health in Mannheim, Germany, hypothesised that MCS is psychogenic in origin, meaning that it is a psychiatric rather than physical condition.
They report that previous studies have found that past trauma experience increases the risk for someone to develop MCS and set out to determine if this was the case.
The researchers recruited 54 participants with MCS, 44 with somatoform disorders (SFD), and 54 who were healthy. SFDs are conditions in which psychological illness produces physical symptoms.
The MCS and SFD patients were selected using a two-step process using screening questionnaires, a medical examination, and structured interviews for MCS and mental disorders.
They found that a large proportion of individuals from all threee groups reported having experienced at least one traumatic event with the exact figures being 70% for the healthy participants, 82% for the MCS patients, and 73% for those with SFD. The small differences were considered insignificant.
The researchers reported that contrary to their expectations no significant differences were found between groups with regard to the proportion with any trauma, traumas fulfilling mental illness criteria, or multiple traumas.
Additionally only two categories of trauma were reported more frequently by those with MCS and SFD. The unspecified 'other' category was reported more frequently by both MCS and SFD patients than healthy participants and the 'life-threatening illness' category was reported more frequently by the MCS group alone.
It is easy to see how the 'other' category frequently checked by the MCS patients might relate to an event such as an acute exposure to pesticides or other toxin which are often cited as the initial triggers for the development of chemical sensitivity. Research carried out by Pamela Reed Gibson, Ph.D., for example found that of 917 people suffering from multiple chemical sensitivity, over 20% reported that their illness started with a single large chemical exposure.
In their influential book Chemical Exposures: Low Levels and High Stakes Nicholas Ashford and Claudia Miller report that as far back as 1966 there are reports of individuals deemed to have recovered from organophosphate poisoning being left with a multitude of symptoms and being unable to tolerate even small amounts of a wide range of chemicals. They go on to describe various mechanisms, including immunological and neurological, which may account for the development of MCS after an acute chemical exposure.
Clearly it would also be expected that those with MCS would also report more traumatic events involving 'life-threatening illness'. Many patients, particularly those with respiratory symptoms, may suffer life-threatening reactions when experiencing a chemical expsoure.
The researchers concluded that "No clear evidence was found for increased rates of trauma experience in IEI and SFD". They did add that larger studies may give different results but this study still helps to question that idea that MCS/IEI is the result of trauma or mental illness.