Home / Science / Dementia Drug Shows Promise for Long COVID
Dementia Drug Shows Promise for Long COVID
24 Jun
Summary
- Long COVID fatigue and depression linked to reduced brain neurotransmitter.
- Existing dementia medication improved symptoms in study patients.
- Herpes virus reactivation identified as a frequent contributor.

Researchers have uncovered a critical link between long COVID symptoms like fatigue and depression and a reduction in the brain's acetylcholine levels. This discovery offers a new understanding of Post-Acute Sequelae of SARS-CoV-2 infection (PASC).
The study, led by the Tokyo Jikei University School of Medicine, indicated that human herpesvirus 6B (HHV-6B) reactivation, evidenced by anti-SITH-1 antibodies, is common in long COVID patients. Notably, those with these antibodies reported more severe fatigue and depression.
Experiments in mice showed that expressing the SITH-1 protein reduced acetylcholine and induced fatigue-like behavior. Treatment with donepezil, a dementia medication that increases acetylcholine, alleviated these symptoms. A retrospective analysis of a trial confirmed donepezil's efficacy in patients positive for anti-SITH-1 antibodies.
These findings suggest donepezil could be a potential treatment for fatigue and depression in specific long COVID cases. Development of a diagnostic method to identify suitable patients is also in progress.