E2 ModeratePreliminaryPEM not requiredCross-SectionalPeer-reviewedReviewed
Standard · 3 min
Neuropsychology and psychology of MCS.
Fiedler, N, Kipen, H, Deluca, J et al. · Toxicology and industrial health · 1994
Quick Summary
This study looked at whether people with multiple chemical sensitivities (MCS) and chronic fatigue syndrome (CFS) have psychiatric issues or thinking problems. Researchers found that both groups reported more psychiatric diagnoses than healthy people, and both groups tended to report physical symptoms rather than emotional ones. Surprisingly, the study did not find significant cognitive impairment in MCS patients, except for a small difference in visual memory.
Why It Matters
This study is important because it directly compares MCS and CFS, helping clarify whether they share similar psychological and cognitive profiles. Understanding whether cognitive deficits or psychiatric factors underlie symptom reporting in these conditions can guide treatment approaches and validate patient experiences.
Observed Findings
Increased rates of Axis I psychiatric diagnoses in MCS and CFS patients compared to healthy controls
MMPI-2 and Toronto Alexithymia Scale profiles consistent with somatization (reporting physical rather than emotional symptoms)
No significant overall cognitive impairment in MCS subjects
Reduced recognition of nontarget designs on visual memory task in MCS patients compared to controls
Somatic symptoms in MCS and CFS overlap with symptoms found in documented neurologic disorders
Inferred Conclusions
MCS and CFS patients exhibit elevated psychiatric comorbidity relative to healthy controls
Both patient groups tend to express distress through somatic rather than emotional symptom reporting
Cognitive dysfunction is not a primary feature of MCS, though subtle visual memory differences may exist
Psychological and neurological symptom presentations may be difficult to distinguish without controlled assessment conditions
Remaining Questions
Do the psychological profiles represent primary psychiatric illness, secondary responses to chronic illness, or manifestations of underlying neurobiological dysfunction?
What This Study Does Not Prove
This study does not prove that psychiatric factors cause MCS or CFS symptoms, only that they co-occur. The cross-sectional design cannot establish causality or temporal relationships. The study also does not explain the underlying neurobiological mechanisms or whether somatization is a coping response to genuine physiological dysfunction versus a primary psychological process.
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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