"As soon as December came around, I was moody, I always wanted to cry, I was feeling suicidal," says Grace Kaiche. "I slept a lot and didn’t want to leave the house and I couldn’t get most of my work done."  

Kaiche has been diagnosed with Seasonal Affective Disorder, or SAD. At 26, she had suffered from SAD for two winters before discovering what for her has been a miracle cure.

SAD is a seasonal depression that hits a significant portion of the population of the Northern Hemisphere, disproportionately women, during the darker winter months.

Up to four per cent of Canadians (as many as 1.2 million individuals) are clinically depressed during the winter, says Dr. Robert Levitan, a Professor of Psychiatry at the Mood and Anxiety Disorders Clinic at the Centre for Addiction and Mental Health (CAMH) and the Cameron Wilson Chair in depression studies at the University of Toronto.

According to Levitan, another 10 to 15 per cent of Canadians suffer from a milder form of SAD called sub-syndromal SAD, which involves the same symptoms but with less severity and disability. The rest of us might silently suffer through a case of what's commonly called the winter blues or winter blahs.

Dr. Robert Levitan

Dr. Robert Levitan, a psychiatrist at the Centre for Addiction and Mental Health (CAMH) in Toronto, recommends light therapy to combat SAD. (Manmeet Ahluwalia/CBC)

Levitan says 80 per cent of SAD sufferers are women between the ages of 18 and 50. For those who are clinically depressed he has been prescribing light therapy based on many years of research by leading scientists around the world – and for Grace Kaiche, the results are brilliant.

Every morning now she sits for half an hour in front of her high-intensity ultraviolet-filtered bright-light unit on loan from CAMH. Eight weeks after first trying bright-light therapy she says, "It literally rescued me. It really surprised me that a light box could make such a big difference in my life." 

'This light is like magic'

Kaiche adds, "From the very first day I felt a change. I’ve started going to the gym again.  Now I get excited to use the light therapy because I know that my energy level will increase and my negative thoughts will disappear."  

She adds, "This light is like magic."

When Kaiche became so depressed in winter, she would not have guessed that her lethargic mood might have been a survival tactic of our evolutionary past.

Levitan and other scientists who study mood disorders believe that SAD really is a vestige of our cave-dwelling ancestors.  

"We think that Seasonal Affective Disorder is something in our genes from our past and in modern society it becomes a nuisance at best, and in severe cases quite a serious problem that requires urgent treatment."

He explains: "Conserving energy and protecting ourselves during the ice age when food resources would have been sparse used to be very adaptive and helpful to our ancestors, especially women in their child-bearing years."

But how could something that once helped humans survive through long harsh winters become a debilitating disorder for some people today?

Levitan says,  "We’re prolonging our work day far beyond where nature would permit it."

The mood change has to do with how our serotonin levels are influenced by light, he says. 

"We are affected by having to remain productive in the decreased hours of sunlight. In our distant past we’d be hibernating," says Levitan.

Suicidal thoughts

Kaiche was feeling more and more like acting on her suicidal thoughts when she went to her family doctor, who prescribed an anti-depressant.

"I was worried about the side effects of mood-altering drugs," says Kaiche, but she tried them anyway and found they didn’t really work for her.

Then she found Levitan and his clinic at CAMH. Kaiche became a subject in an ongoing study about light therapy and winter depression.  

Her experience with light therapy is backed up through scientific research. Levitan was co-author of a large study that found "over time the chance of responding to light was exactly the same as responding to medications." 

The study also found light therapy tended to work immediately, with fewer adverse side effects.

Levitan says that by April or May the longer daylight hours usually will help patients feel completely normal again.

During Kaiche's last session, Levitan advises her to monitor her progress. "I think it’s just a matter of continuing through the winter, probably until the end of March or so, and then starting again next fall and you should be fine."

Levitan emphasizes the need to avoid ultraviolet light which is dangerous to the eye. There are several commercially-available UV-filtered units that have been designed specifically for the safe treatment of SAD.


  • A previous version of this story erroneously stated that ultraviolet light is used to treat seasonal affective disorder. In fact, the lamp filters out ultraviolet light.
    Feb 26, 2015 9:57 AM ET