TORONTO -- As the days grow greyer and the trees start shedding their leaves, mental health professionals are starting to worry about how hard seasonal depression could hit during a pandemic.

“The reason we’re keeping an eye out on seasonal symptoms more this year than usual is that the pandemic is going to make it even more difficult for people to get sufficient environmental light to stave off this problem,” Dr. Robert Levitan, a psychiatrist with the Centre for Addiction and Mental Health (CAMH), told CTV News Channel.

The late fall and winter months bring mood changes to many across the general population, with varying levels of severity.

“I’ve seen many patients who have difficulty around this time of year, so as the days get very short and light becomes much less available, a large proportion of the population starts to feel slowed down,” Levitan said. “They start to feel fatigued, less able to concentrate and focus, some people start to crave carbohydrates and gain a lot of weight."

Around a third of the population suffers a negative drop in mood at this time of year, according to CAMH, while three to five per cent of the population develop seasonal affective disorder (SAD), a form of depression that can be severely draining.

“This is something that’s happening in the whole population to different degrees, and we tend to see the most severe cases, that three to five per cent, at CAMH, but in the population as a whole there’s lots of people who will be affected by the lack of light,” Levitan said.

It’s daunting to be facing down winter, and the spectre of seasonal mood changes, during a pandemic that has spurred an increase in anxiety, stress and depression among numerous people across the country. Several studies have shown that the pandemic has negatively affected the mental health of wide swaths of people, from anxiety-related to the threat of the virus itself, to economic stress caused by the disruption of regular schedules.

A recent study from CAMH showed that women and those with children were experiencing a significantly higher increase in anxiety as a result of the pandemic, with a quarter of all women reporting moderate to severe anxiety, and almost 30 per cent of parents with children under 18 reporting that they had been feeling depressed.

Levitan’s concern as winter looms is that the months of being cooped up due to a pandemic will cause the conditions of winter -- less light and weather that forces you inside -- to be even more stressful.

“People are going to be inside a lot more, they’re going to be less likely to get up in the morning on time, which is a very good thing to do to fight seasonal symptoms, and they’re going to get into a routine that will make them more sluggish, and therefore, for some people, have a higher rate of depression as well,” Levitan said.

So what can people do to fight off the two-punch combo of COVID-19 anxiety and the winter blues?

There are a variety of strategies, depending on the severity of symptoms, Levitan said.

For those three to five per cent who are diagnosed with seasonal affective disorder, the most common treatment is “bright light therapies,” he explained.

“We just directly try to replace the lack of light with ultraviolet-filtered bright light units that people use for about a half an hour each morning, right through the fall/winter period,” Levitan said. “We know that this is very effective for most patients with seasonal depression.”

There’s also regular anti-depressant medications available for those who don’t respond to the light. The lights themselves, called SAD lamps or light therapy devices, can be purchased from many retailers in Canada, as no prescription is required. Although many products advertise themselves as helping with SAD, fluorescent light boxes have been found effective in more tests, as compared to devices such as light visors or dawn simulators, according to the Faculty of Medicine at the University of British Colombia. They add that light therapy could be harmful to those with certain medical conditions, such as retinal eye disease.

Light lamps aren’t the only answer to a persistent bad mood in winter, however.

“For the population as a whole, I would say there’s lots of things one can do in addition to using light therapy,” Levitan said.

“For example, I think during the pandemic, it’s going to be particularly important for people to have a morning routine, whereby they wake up at a reasonable hour, and try to stay active, try to have social interactions early in the day, if they can, to try to get some exercise, and certainly, if there’s any hint at all of decent weather, to get out there and walk around, even for five minutes outside in the morning.”

One way to think about is “trying to recreate what a normal workday would be,” he said.

“Because really what the task is, is something that we call behavioural activation. You want to get your mind and body into an active state early in the day, which builds momentum and makes you feel a lot better. And if you don’t do that, if you allow yourself to get sluggish, it tends to have a momentum that can be deleterious.”