Brain scans of people with long COVID point to a missing chemical messenger
What happened
Scientists in Canada have used brain scans to look inside the brains of people with long COVID. What they found may help explain two of its most common and most frustrating symptoms: crushing tiredness and brain fog. The work was done at the Centre for Addiction and Mental Health in Toronto. It was published in the journal eBioMedicine and reported on 21 September 2026. The team used a type of scan called PET, which stands for positron emission tomography. Unlike an ordinary scan that shows the shape of the brain, a PET scan can show what the brain is doing. In this case it was used to count markers of a particular kind of brain cell. Those cells release dopamine. Dopamine is a chemical messenger. It is often talked about as the "reward" chemical, but that is only part of the story. It also helps drive motivation, movement and some kinds of memory. The researchers compared people with long COVID against healthy volunteers. In the long COVID group, markers of dopamine-releasing cells were substantially lower across a region of the brain called the striatum. The pattern was not random. Different parts of the striatum lined up with different symptoms. Lower readings in one part, the ventral striatum, went along with loss of motivation. Changes in another part, the dorsal putamen, went along with slowed movement. Reductions in the caudate putamen went along with memory difficulties. Dr Jeffrey Meyer, who led the work, said: "Our findings provide compelling evidence that long COVID involves the loss of dopamine-releasing neurons." The same team had previously found raised levels of inflammation in the brains of people with long COVID, particularly in the areas that are rich in dopamine. This new result builds on that.
Why this matters
People with long COVID have spent years being told, in one way or another, that the problem might be in their head. This research suggests that it is in their head, but not in the way that phrase usually means. Brain fog and exhaustion are hard to measure. There is no blood test for them. That has made them easy to dismiss and hard to treat. A scan that shows a physical difference changes the conversation. It also matters because it points somewhere specific. If the problem involves dopamine-releasing cells, then treatments that act on dopamine become worth testing. Medicines that affect dopamine already exist, because they are used in other conditions. That does not mean they will work here. But it gives researchers a place to start, rather than guessing. The research team has said it plans a clinical trial targeting dopamine function to see whether symptoms improve. There is a wider point too. Long COVID is not one thing. Different people have very different symptom patterns. Findings like this help split a vague label into more precise pieces, and precise pieces are easier to treat.
What the evidence actually says
It is worth slowing down here, because this is the kind of finding that is easy to over-read. This was a brain imaging study comparing two groups. The published report did not state the number of participants, and PET imaging studies are usually small, because the scans are expensive and involve a small dose of radiation. A small study can find something real. It can also find something that does not hold up when repeated in a larger group. Until it is replicated, the sensible position is interest, not certainty. The study also shows an association, not a cause. It found that people with long COVID had lower markers of dopamine cells, and that the pattern matched their symptoms. It did not show that the virus destroyed those cells, or prove that low dopamine is what produces the tiredness. Something else could be driving both. The specific marker measured was VMAT2, a protein involved in packaging chemical messengers inside nerve cells. Lower VMAT2 is taken as a sign of fewer working dopamine cells, but it is an indirect measure. What the study does do well is line up biology with symptoms in a way that is hard to explain by chance. Three different brain regions matched three different symptoms in the directions you would predict. That internal consistency is a point in its favour. What it does not do is offer a treatment today. There is no dopamine medicine you can ask for on the strength of this paper, and no scan your GP can send you for to check. The planned trial has not yet reported.
Qurexa perspective
This is a research story rather than a service story, but one detail is worth drawing out. The symptoms described here, loss of motivation and difficulty with memory, are exactly the symptoms that make managing medication harder. Ordering a repeat prescription on time, getting to a pharmacy, remembering whether you took this morning's dose: all of these lean on the parts of thinking that long COVID disrupts. We deliver prescriptions across Lincolnshire, and fatigue is one of the most common reasons people tell us a trip to the pharmacy is difficult. If you or someone you look after is finding the practical side of medication hard at the moment, it is worth knowing that home delivery is available, and that pharmacy teams can set up reminder systems and multi-compartment packs. That is a genuinely useful thing to ask about, whether you use us or anyone else.
Practical advice
If you are living with long COVID, this study does not change what you should do tomorrow. But a few things are still worth saying. Keep talking to your GP. Long COVID is a recognised condition, and there are specialist services in parts of England, though access varies by area. Ask what is available locally. Be cautious about anything sold as a cure. Findings like this one tend to be followed quickly by supplements and private clinics claiming to "restore dopamine". There is no evidence behind that, and some products interact with prescribed medicines. Pacing still has the best evidence of the practical approaches. That means planning activity so you stop before you crash, rather than pushing until you do. It is unglamorous and it is frustrating, but it is what most specialist services teach. Write things down. If memory is affected, external systems help more than effort does. Lists, alarms, a single notebook, a pill organiser. And tell your pharmacist what is going on. They can often simplify a medicine routine, line up repeat dates so everything arrives together, or arrange delivery. Many people never think to ask.
What to know
Researchers at the Centre for Addiction and Mental Health in Toronto used PET brain scans to compare people with long COVID against healthy volunteers. They found substantially lower markers of dopamine-releasing nerve cells across the striatum, a region involved in motivation, movement and memory. The pattern matched people's symptoms: reduced readings in specific areas lined up with loss of motivation, slowed movement and memory problems. This is early work. It is an imaging study, it shows an association rather than a cause, and it has not yet been repeated in a larger group. It does not point to any treatment you can get today. The team plans a trial testing whether targeting dopamine helps. What it does do is give a biological anchor to symptoms that have often been doubted, and a clearer target for the research that follows. Sources: ScienceDaily, "Brain scans reveal a possible cause of long COVID fatigue and brain fog", 21 September 2026, https://www.sciencedaily.com/releases/2026/09/260920222412.htm; Liu, Y.K. et al., "Loss of vesicular monoamine transporter 2 in striatum of long COVID and relationship to neuropsychiatric symptoms", eBioMedicine, 2026; 130: 106339, https://doi.org/10.1016/j.ebiom.2026.106339; Centre for Addiction and Mental Health (CAMH), Toronto, https://www.camh.ca This article is for general information and does not replace advice from a doctor, pharmacist or other qualified healthcare professional. If you are struggling with long COVID symptoms, speak to your GP.
Related articles
Six hours, not never: the ICU filter notice the MHRA issued today
The UK's medicines and devices regulator has issued a new safety notice to hospitals, and it is about timing. On 13 October 2026 the Medicines and Healthcare p…
Eight pages to a minister: what the data guardian says trust is worth
On 12 October 2026, the government published a letter about who should be trusted with NHS patient data. It was written by Dr Nicola Byrne, the National Data G…
Update: the tests came back, and it was not plague
This is a follow-up to a story we covered on 5 October, when nearly 200 people were being monitored after the death of a laboratory worker in Siberia. There has…