DeLuca, J, Johnson, S K, Ellis, S P et al. · Journal of psychiatric research · 1997 · DOI
This study looked at whether the way ME/CFS starts—suddenly or gradually—affects thinking abilities and mental health. Researchers tested 36 ME/CFS patients on memory, concentration, and processing speed, and compared them to healthy controls. They found that people whose ME/CFS came on gradually were more likely to have depression or anxiety, while those with sudden onset had more severe memory problems.
This study identifies ME/CFS as a clinically heterogeneous condition with distinct cognitive and psychiatric profiles depending on illness onset pattern. Understanding these subgroups may help clinicians better identify and manage individual patients' needs and could guide future research into whether different onset mechanisms require different treatment approaches.
This study does not establish that onset mode causes the differences in cognitive or psychiatric outcomes—it only shows they are associated. The cross-sectional design means we cannot determine whether psychiatric conditions preceded or followed ME/CFS onset, nor whether cognitive differences might reflect different underlying disease mechanisms or simply reflect different symptom patterns. A small sample size (36 patients) 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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