What is brain fog?
The term 'brain fog' is used to convey a broad but characteristic set of symptoms, implicating cognition (particularly attention, memory, and language), affect, and fatigue.
Brain fog is related to, but dissociable from, cognitive performance. Fatigue and affect influence subjective brain fog and mediate cognitive performance deficits across diagnoses.
Divergent neural correlates suggest a heterogeneous aetiology. Researchers should provide clear definitions when studying brain fog, preferably replacing or complementing it with more precise terms where possible [e.g., 'post-coronavirus disease 2019 (COVID-19) neuropsychiatric symptoms' rather than 'COVID-19 brain fog’].
The authors suggest that future research should conduct transdiagnostic comparisons of brain fog using a standardised set of measures to fractionate the distinct constructs that brain fog conflates and enable precise characterisation.
https://www.cell.com/trends/neurosciences/fulltext/S0166-2236(25)00017-7
