Fiedler, N, Kipen, H M, DeLuca, J et al. · Psychosomatic medicine · 1996 · DOI
This study compared people with multiple chemical sensitivities (MCS), chemical sensitivities without a clear trigger (CS), and chronic fatigue syndrome (CFS) to healthy controls. Researchers found that chemically sensitive patients reported more lifestyle disruption and avoided more substances than CFS patients, but all three patient groups had higher rates of psychiatric conditions and unexplained physical symptoms compared to healthy people. Interestingly, standard memory and thinking tests did not show significant differences between groups, suggesting that cognitive problems in these conditions may not show up on typical office-based tests.
This study provides evidence that ME/CFS, while associated with elevated psychiatric symptoms, is not primarily a psychiatric disorder—most CFS patients (61%) did not meet psychiatric diagnostic criteria. The findings suggest that the neuropsychological impairments patients report may require specialized testing conditions rather than standard office-based assessments, supporting the biological basis of these illnesses.
This study does not prove that chemical sensitivities or CFS are caused by psychiatric conditions; the majority of patients with these conditions did not meet psychiatric diagnoses. Cross-sectional design cannot determine whether psychiatric symptoms arose before, after, or independently of CFS onset. The study also cannot explain why standard cognitive tests failed to detect reported cognitive deficits, leaving open the question of whether impairments require specific provocation conditions.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
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