How Much Do You Really Know About Seasonal Depression?
December 12, 2025 | 3 min read
How can a simple change in season affect the energy, focus, and mood of up to 15% of Canadians?1 “Seasonal depression – known clinically as Seasonal Affective Disorder – is a recurring depression that typically appears at the same time each year,” explains Dr. Gustavo Turecki, psychiatrist and Scientific Director at the Douglas Research Centre.
Dr. Turecki explains below what seasonal depression is and isn’t. Test your level of understanding of this important, and often underestimated, mental health issue.
Seasonal depression and winter blues are the same thing.
FALSE. Although the two terms are often used interchangeably, Dr. Turecki explains that they refer to different experiences. “The winter blues are a general sadness or dip in mood that many people naturally experience once summer ends,” he explains. “Seasonal affective disorder, on the other hand, is a clinical form of depression that can significantly impact sleep, energy levels, and our basic ability to function from day to day.”
Seasonal depression only occurs during the winter.
FALSE. It most commonly begins in fall or winter, when daylight hours decrease. However, it can also occur at other times of the year. “Although less common, a form of seasonal depression can occur in the summer, with opposite symptoms like insomnia and restlessness,” says Dr. Turecki.
Tip! Mental health and counselling services, and employee and family assistance programs (EFAPs) can be a valuable source of confidential counselling at any time of year. Check if your benefits plan includes these resources.
Learn more: Mental health & counselling services - Group Benefits │ Manulife
The lack of sunlight plays a role in seasonal depression.
TRUE. While diminishing exposure to light isn’t the only factor explaining seasonal depression, it significantly influences key biological systems. Shifts in light levels can disrupt the circadian rhythm, which helps regulate sleep, appetite, and alertness.
Seasonal changes also trigger biological cues that may influence our behaviour, depending on the time of year. “Our bodies carry evolutionary remnants that prompt us to adapt to our environment,” says Dr. Turecki. “As winter approaches, some people experience increased fatigue and sleepiness, often leading to a dip in activity—much like animals preparing to hibernate.”
Light therapy is an effective treatment for many people with seasonal depression.
TRUE. Light therapy lamps offer a simple and reasonably affordable way to ease symptoms of seasonal depression. “It doesn’t work for everyone, but it’s a good first option to try,” says Dr. Turecki. Research suggests using a light box that emits 10,000 lux for 30 minutes (or 5,000 lux for 60 minutes), ideally before 8 a.m.2 Avoid looking directly into the light.
Tip! Physical activity is a great way to reduce stress, balance your mood and improve sleep. If certain health or mobility issues are preventing you from reaching your goals, check if your group benefits plan includes coverage for physiotherapists, kinesiologists, or other paramedical services to get support.
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Seasonal depression isn’t that serious; you don’t need help to deal with it.
FALSE. Dr. Turecki recommends speaking with your family doctor or seeking support from a mental health professional. “Symptoms, their intensity, and duration can all vary widely from person to person,” he adds. “In some cases, antidepressants may be needed—for example, to treat an underlying depression that lingers even after spring returns.”
How can you recognize if you’re prone to it — and if you are, are there strategies that can minimize its effects? “We often link the idea of prevention to physical health, but it’s just as important for mental health,” says Jennifer Foubert, assistant vice president and head of product and growth for Group Benefits at Manulife Canada. “Learning about mental health conditions can help you spot the signs earlier.”
This story was originally published in La Presse on November 16, 2025
This article is for informational purposes only. It is not intended to diagnose or treat a condition. If you have questions or concerns about your specific situation or are seeking medical advice, contact your medical doctor or your healthcare provider.
The Douglas Foundation
The Douglas Foundation's mission is to unite great minds and build resources to improve the mental health of all, today and tomorrow. Founded in 1972, its mission is to fund the development of the Douglas Institute: patient care and their environment, research in neuroscience and mental health, as well as education and training. Manulife supports the Douglas Foundation in alignment with our Impact Agenda and our commitment to Empowering sustained health and well-being to support the journey towards a better life.