Symptom cluster
Brain fog and cognitive impairment
Trouble thinking, focusing, and remembering. Four mechanisms converge here, which is why this is real and not a matter of effort. This page covers: Brain fog / cognitive impairment (executive, working memory, attention, processing speed), Population-level cognitive deficit (~3-9 IQ points).
What causes it
The leading explanations, each with its evidence grade and audit status.
Blood-brain barrier disruption produces Brain fog / cognitive impairment (executive, working memory, attention, processing speed).
Neuroinflammation / microglial activation produces Brain fog / cognitive impairment (executive, working memory, attention, processing speed).
Gut-serotonin axis produces Brain fog / cognitive impairment (executive, working memory, attention, processing speed).
Immune dysregulation & autoimmunity (pathogenic IgG) produces Brain fog / cognitive impairment (executive, working memory, attention, processing speed).
EBV / herpesvirus reactivation produces Brain fog / cognitive impairment (executive, working memory, attention, processing speed).
What has been tried
No treatment is approved. Each row shows how strong the evidence is, what it was measured on, and any safety or conflict flag.
Guanfacine + N-acetylcysteine improves Brain fog / cognitive impairment (executive, working memory, attention, processing speed).
RECOVER-NEURO found small, nonspecific gains from cognitive training and brain stimulation, with no clear winner. Logged as low-grade candidates.