Skip to content

Column: Feeling SAD? The weather and your mood

Spring is in the air! For many Canadians, the melting snow and budding trees means swapping out a parka for a windbreaker.
Seasonal Affective Disorder, also known by the appropriately acronym SAD, affects between two and three per cent of Canadians, but more than a quarter of Canadians experience some kind of mood change related to the seasons. Photo supplied
Spring is in the air! For many Canadians, the melting snow and budding trees means swapping out a parka for a windbreaker. However, for those affected by seasonal mood changes, the onset of spring can mean a whole lot more than just a change of wardrobe.

Approximately 35 per cent of Canadians experience mood changes starting in late fall or early winter. While the majority of cases are mild — aptly named the Winter Blues — between two and three per cent of Canadians are diagnosed with Seasonal Affective Disorder, or SAD.

Symptoms of SAD can include irritability, loss of energy and feelings of hopelessness or despair. The direct cause of the disorder isn’t crystal clear, but researchers believe that a combination of factors might be at play.

To explore the biological clock theory, we have to go way back in human history. Back to a time when colder weather meant that there was less to eat, and that humans had to conserve what energy they had.

The shorter days trigger the body’s biological clock, or circadian rhythm, to slow down. Unfortunately, modern life doesn’t usually accommodate our biological clocks, and a fast paced work or family life means that slowing down is simply not an option.

This disconnect from the biological clock can cause excessive fatigue, one of the symptoms of SAD and the Winter Blues.

Chemical factors in the brain may also play an important role in the more severe cases of Seasonal Affective Disorder. Researchers have found that levels of serotonin and dopamine, two chemicals in the brain that are responsible for mood, change in individuals affected by SAD.

These chemical factors are complicated, as researchers are finding both increased and decreased levels of dopamine in patients with the disorder. This imbalance is likely caused by a drop in sunlight, and treatment through light therapy can help restore a healthy balance in serotonin and dopamine levels.

Finally, the shorter days and colder weather can affect day-to-day behaviour, having a large impact on how someone feels. People experiencing Winter Blues or SAD can be less motivated to exercise and experience more cravings for foods high in sugar and carbohydrates. These types of behaviours can make people feel generally unwell and make them less motivated to do what they enjoy.

With spring weather around the corner, things are looking up for Canadians affected by seasonal mood changes. The longer days and warmer weather can help reset the biological clock, sort out chemical imbalances, and encourage Canadians to get back outside.

Yvonne Kirkpatrick is a science communication graduate student at Laurentian University. She has a Bachelor of Arts and Sciences degree from the University of Guelph. Have a burning science question? Send it to