Behavioural problems associated with the chronic fatigue syndrome.
Smith, A P, Behan, P O, Bell, W et al. · British journal of psychology (London, England : 1953) · 1993 · DOI
Quick Summary
This study tested whether people with ME/CFS actually experience the memory, concentration, and coordination problems they report. Researchers gave 57 ME/CFS patients and 19 healthy controls a series of computerized tests measuring thinking speed, memory, attention, and motor skills. ME/CFS patients performed worse on many tests—they were slower at tasks requiring coordination, had trouble focusing, and struggled with complex reasoning—even though their depression and anxiety levels didn't fully explain these differences.
Why It Matters
This study provides objective evidence that cognitive and motor complaints in ME/CFS are real measurable deficits, not simply psychological symptoms or complaints without physical basis. Demonstrating that these impairments exist independently of depression and anxiety helps validate patient experiences and supports the neurobiological nature of ME/CFS, potentially improving recognition by healthcare providers.
Observed Findings
CFS patients showed significantly slower performance on psychomotor tasks compared to controls
CFS patients demonstrated impaired attention and increased visual sensitivity
CFS patients exhibited slowed semantic memory retrieval and logical reasoning, while basic memory span remained intact
Patients reported substantially higher levels of depression, anxiety, and cognitive failures than controls
Performance differences persisted even after accounting for differences in psychopathology scores between groups
Inferred Conclusions
Cognitive and motor dysfunction in ME/CFS represent objective, measurable impairments rather than subjective complaints without physiological basis
These behavioral and cognitive deficits are not simply secondary to mood disturbances like depression and anxiety
Underlying neurological dysfunction likely explains the observed patterns of selective cognitive impairment and motor slowing in ME/CFS
Remaining Questions
What specific neurological or neurochemical mechanisms cause the observed cognitive and motor deficits in ME/CFS?
Do these cognitive and motor impairments correlate with disease severity, symptom duration, or specific biomarkers?
What This Study Does Not Prove
This study does not prove what causes the cognitive and motor dysfunction—only that it exists and is not entirely explained by mood disorders. As a cross-sectional snapshot, it cannot establish whether these deficits develop before, during, or after ME/CFS onset, nor whether they are reversible or progressive. The modest sample size and single-timepoint assessment limit generalizability to all ME/CFS populations.