Malt, U F, Nerdrum, P, Oppedal, B et al. · Psychosomatic medicine · 1997 · DOI
This study looked at 99 people who believed their symptoms were caused by mercury in dental fillings and compared them to 272 control subjects without these concerns. The dental-amalgam group reported far more physical symptoms across their bodies, anxiety, depression, and fatigue. The researchers found that many in this group had mental health conditions like anxiety disorders and depression, and about one-third reported symptoms similar to chronic fatigue syndrome.
This study is relevant to ME/CFS researchers because approximately one-third of the dental-amalgam-attributed patients reported chronic fatigue syndrome symptoms, suggesting overlap between unexplained symptom syndromes. Understanding the relationship between symptom attribution patterns, mental health comorbidities, and medically unexplained fatigue may inform how ME/CFS presents in some patients and how health beliefs shape symptom reporting.
This study does not prove that dental amalgam fillings cause or do not cause the reported symptoms—it only shows that patients who attribute symptoms to amalgam have high rates of mental health conditions and somatic symptoms. The design cannot establish whether psychiatric comorbidities are primary or secondary, nor does it test biological mechanisms. The self-referred nature of the amalgam group introduces selection bias that limits generalizability.
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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