Researchers at Toronto’s Centre for Addiction and Mental Health (CAMH) reported evidence of lower dopamine-terminal marker levels in the brains of people with long COVID. The case-control study, published in eBioMedicine on July 10, 2026, compared PET scans from 24 people with long COVID and 24 age-matched healthy controls. The journal published a corrigendum on September 5; the study’s findings should be read alongside that correction.
The researchers measured VMAT2 binding, a PET marker used to assess dopamine-releasing nerve-terminal integrity, in three parts of the striatum: the ventral striatum, dorsal putamen and dorsal caudate. Levels were significantly lower in the long-COVID group across all three regions. A larger group of 43 healthy controls was also used for exploratory analyses.
The study reported associations between lower marker levels and symptoms: the ventral striatum with apathy, the dorsal putamen with slowed movement, and the caudate with memory decline. The memory association was exploratory. These correlations do not show that the marker changes caused the symptoms, nor that the changes represent permanent neuron loss. A separate scientific commentary noted that reduced VMAT2 binding does not by itself establish irreversible damage.
The researchers suggested that treatments affecting dopamine signalling could be studied in future trials. CAMH planned to start a clinical trial in the coming months, according to the source report. A study author, Jeffrey Meyer, had filed a January 2026 patent application related to rasagiline and a tyramine-based dopamine-precursor approach for long COVID, as reported by Pharmacy Times. The patent disclosure is relevant context when evaluating proposed treatment directions.
The study was small and relied on scans taken at one point in time. It does not establish whether the observed differences persist, improve or progress, and it is not evidence that any treatment is effective. Long COVID is estimated to affect about 5% of the global population; no evidence-based treatment was established by this study.
Verified: Study design, 24+24 sample, VMAT2 findings, symptom associations and publication details: the original eBioMedicine paper indexed by PubMed. The September 5 corrigendum is also listed by PubMed. Supporting coverage: Medical Xpress, ScienceDaily and Pharmacy Times. Uncertainty: “Strongest evidence to date” is the researchers’ characterization. The patent filing should be considered when assessing potential conflicts of interest. Not available: An independent replication and the clinical trial’s registration number were not available in the source material.