CAMH study links long COVID fatigue to dopamine neuron damage

September 21, 2026 at 05:00 AM2 min

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A CAMH-led brain imaging study found lower dopamine neuron markers in long COVID patients, linking the condition to fatigue and brain fog. The findings, published in eBioMedicine, may explain persistent symptoms and point to new treatments.

Key Facts

Long COVID affects about five per cent of the global population, including roughly two million people in Canada.
PET scans showed substantially lower dopamine neuron marker levels in long COVID patients across all major areas of the striatum.
Lower marker levels in the ventral striatum were linked to greater loss of motivation, while reductions in the dorsal putamen were associated with slower movement.
The study was published in eBioMedicine and led by scientists at the Centre for Addiction and Mental Health (CAMH).

Dopamine System Changes

Researchers used positron emission tomography (PET) to measure a marker associated with dopamine neuron health in people with long COVID and healthy participants. The study found substantially lower levels of this marker in people with long COVID across all major areas of the striatum, a brain region that regulates motivation, movement, and thinking. Lower marker levels suggest a reduced density of dopamine nerve terminals. Different patterns of marker loss were associated with different symptoms: lower levels in the ventral striatum were linked to greater loss of motivation, reductions in the dorsal putamen to slower movement, and lower levels in the caudate putamen to memory difficulties.

Inflammation Link

The new findings build on previous work by the same research team showing unusually high levels of brain inflammation in people with long COVID. That inflammation appeared especially pronounced in regions containing large numbers of dopamine-releasing neurons. Dr. Jeffrey Meyer, senior author of the study, said the findings provide compelling evidence that long COVID involves the loss of dopamine-releasing neurons. He noted that this kind of injury is known to produce symptoms like lack of motivation and motor slowing, and may contribute to memory difficulties in other neurological conditions.