This mood disorder is said to commonly flare up in the fall and winter months.
Professor of neuroscience at the University of Lethbridge, Robert J. McDonald says "it's sort of on a spectrum."
According to Alberta Health Services, three to four percent of Canadians battle this mood disorder and McDonald says seven percent of these people battle the rarest form, which is a severe form of depression.
"You have a clock in your brain, a 24-hour clock, that runs deep, deep, deep inside your brain," says McDonald of the human body's 'master-clock.'
"It turns out that not only do you have this master clock, but you have peripheral clocks all over your brain and body; your stomach, your liver, different parts of your brain," he says.
McDonald explains that the 'master-clock' communicated with the other clock, but the peripheral clocks also send signals back.
"If there's a desynchrony between the master clock and those other clocks, you're going to have problems," says McDonald.
McDonald is a faculty member at the Canadian Centre for Behavioral Neuroscience, Canada's first institution of its kind.
For more information, visit: http://www.uleth.ca/artsci/neuroscience