For Susie Goulding the term “brain fog” doesn’t begin to cover it.

That makes it seem like she’s missed her morning coffee.

But she compares the intense and often debilitating memory, focus and concentration issues she’s faced over the past nearly two years to living with dementia.

“It’s completely flipped my life upside down,” said the 54-year-old Oakville resident.

“One day it just hit me like a ton of bricks. Everything was just foggy and I was slow to react,” she recalls. “Then it just got worse.”

Two years into the pandemic, scientists are still trying to understand how COVID-19 can impact the brain. One of the most persistent, and troubling symptoms of the disease is what’s often referred to as “brain fog,” which can leave formerly healthy active people, like Goulding, who was infected with the virus back in March 2020, a shell of their former selves.

But, from a new study led by a researcher at the University of Toronto testing an antidepressant, to Sunnybrook and the Centre for Addiction and Mental Health (CAMH) teams analyzing brain scans, local efforts are underway to understand more about what’s going on, and, hopefully, help some of these patients.

Long COVID, classified by the World Health Organization as “post-COVID-19 condition,” is defined as a diverse range of symptoms including fatigue, shortness of breath, and cognitive dysfunction, usually occurring three months after the first symptoms, and lasting at least two months. In a September 2021 brief, Ontario’s COVID-19 Science Advisory Table put the “conservative” estimate of Ontarians living with this condition at somewhere between 57,000 to 78,000, noting that vaccination is “likely protective” against it.

It’s a “collection of symptoms and signs that are really poorly understood,” said Dr. Roger McIntyre, a professor of psychiatry and pharmacology at the University of Toronto.

“Unfortunately, there are a lot of people affected by this, and they don’t know what to do. A lot of people can’t work, they can’t take care of their kids, they can’t do their daily chores, and so on, so people are very very impaired,” said McIntyre, who is also the head of the Mood Disorders Psychopharmacology Unit at the University Health Network.

McIntyre is leading a double blind study recruiting people from across the province to test an antidepressant called vortioxetine, with the hope it can help those still struggling with COVID’s brain impacts. Half the participants will get the antidepressant, and the other half a placebo, without knowing which one they’ve received.

When people are depressed and suffer from brain fog, he said, there’s often something wrong with their immune system. So his theory is that this anti-inflammatory might also help long COVID patients with brain issues.

There is precedent, he said, for a viral infection setting off a “cascade of events” that impacts the nervous system and brain. A recent Harvard study, for example, made headlines for finding a higher risk of multiple sclerosis in people who’d had the Epstein-Barr virus, which can cause mononucleosis.

There’s also some evidence of a connection between strep throat and obsessive compulsive disorder.

Usually the research would come first, before potential treatments, McIntyre said. But with so many people suffering from lingering COVID impacts and so little insight about what’s wrong with them, it changes the game.

“Yes, the horse should be in front of the cart, but sometimes they should walk in tandem,” he said.

“We really don’t have enough studies right now that are broadly aiming to help people with this condition. We kind of need to walk and chew gum at the same time, we need to understand what this problem is, but we also need to figure out ways to treat it.”

As the pandemic drags on, more pieces of the puzzle are starting to fall into place. One theory is that the virus can enter through the nose. There is also some evidence that it can harm the brain by reducing its blood flow.

A recent pre-print study led by researchers at Stanford and Yale universities, which has not yet been peer reviewed, suggests even mild COVID can cause cognitive impairment. The study examined the brains of nine people who were positive for the virus after they died (not all from the disease) and found evidence of inflammation of the brain, similar to what some patients report after cancer chemotherapy treatments.

Closer to home, researchers at Sunnybrook and CAMH are looking at brain scans of people who are still alive, but dealing with the disease’s effects.

Simon Graham, a senior scientist at the Sunnybrook Research Institute, is leading an ongoing Canadian Institutes of Health Research-funded neuroimaging study examining the impact of long-haul COVID on brain function over time.

“We know that the impact on the brain of COVID and the long-haul COVID condition is a very complex one,” he said. “So there’s multiple mechanisms by which the brain could become infected.”

This is an important area of research, he added, as long-haulers are still going to be there, even if new infections are brought under control.

“We’re going to be left with people that have this lingering illness.”

Dr. Jeffrey Meyer, head of the Neurochemical Imaging Program in Mood and Anxiety Disorders at CAMH, is leading another study conducting brain scans of people who have long-haul COVID and depression.

“We suspect that they get a lot of brain inflammation and there are some cells in the brain that when they’re inflamed they make some changes,” said Meyer, who is also a Canada Research Chair in the neurochemistry of major depression.

“We’re trying to get the right handle on the magnitude of the issue,” he said, adding people who volunteer for the study can help to contribute to new treatments for long-haulers.

Our understanding of COVID has come a long way since March 2020, but many people still think of COVID as a respiratory illness, said McIntyre. And they are surprised that it can have such an impact, months or even years later, even if their case was technically mild, like Goulding’s, and they didn’t end up hospitalized.

“They’re coming to us saying, ‘You know, I used to be this, I used to be that, I got COVID, it wasn’t even all that severe, and now I can’t even function, I’ve got no energy, my mind is completely foggy and I can’t do anything’, and these are high functioning people in many cases.”

Goulding, who plans to participate in McIntyre’s study, used to be an avid skier, and worked as a floral designer. Her brain fog symptoms settled in about eight weeks after she believes she was first infected.

She suffered from a range of symptoms including tinnitus and heart issues. But for her what happened to her brain was the worst part.

She was nervous driving for months, putting sticky notes around the house to remind herself of simple everyday tasks, once leaving a kettle on and breaking the glass top of her stove. She couldn’t work.

Goulding was helped immensely, she said, by an interdisciplinary rehab program at an integrated-care clinic in Burlington, that included physiotherapy, and exercises like word puzzles, to practice her mental skills.

She’s working again, but in a new career as a medic on film sets, because she doesn’t have the stamina to go back to her old job as a floral designer.

As for skiing, she’s not back on the slopes yet, and still needs to work up some strength and endurance. Maybe by next season.

“I am hopeful,” she said.

May Warren is a Toronto-based breaking news reporter for the Star. Follow her on Twitter: @maywarren11