Seasonal Affective Disorder in Canadian Winter
By late December, Toronto gets about nine hours of daylight each day. Many people leave for work in the dark and come home in the dark, catching sunlight only if they happen to be by a window at the office. If your mood, energy, and patience seem to drop along with the light each year, it’s worth knowing about seasonal affective disorder (SAD).
SAD is a form of depression that follows the seasons. It usually arrives in the late fall, settles in over winter, and lifts as the days get longer. A pattern like this has one upside: you can plan for it. Below, we’ll look at how to spot SAD, what research says causes it, and how everyday habits and therapy can help you get ahead of the darker months.
What Is Seasonal Affective Disorder?
Seasonal affective disorder is depression with a seasonal pattern. The Canadian Psychological Association (CPA) describes it as a condition that appears in the fall and fades in the spring or summer. A less common summer pattern also exists, where symptoms start in the warmer months.
It's more common than many people realize. The CPA estimates that about 15% of Canadians will experience at least a mild form of SAD in their lifetime, and 2 to 3% will experience a more serious form.
At Radcliffe Psychotherapy Clinic, we approach SAD much like other forms of depression. Your therapist will collaborate with you to see what happens to your thoughts, routines, and emotions during the colder months. We also encourage clients to see their family doctor at the same time, because the physical side of SAD is just as important. Your doctor can determine if factors like vitamin D levels are coming into play, and whether tools such as light therapy make sense for you.
About 15% of Canadians will experience at least a mild form of SAD in their lifetime, and 2 to 3% will experience a more serious form.
Seasonal Affective Disorder Symptoms
Plenty of people get the winter blues in January when the holiday lights come down. But what sets SAD apart is its pattern: the same changes return around the same time each year, and they start to interfere with work, relationships, and daily life.
The most common seasonal affective disorder symptoms in the winter pattern include:
Low mood: Feeling sad, empty, or down most of the day, nearly every day
Loss of interest: Hobbies, friends, or work you usually enjoy start to feel like chores
Oversleeping: Sleeping longer than usual and still waking up tired
Carbohydrate cravings: Reaching for starchy or sugary foods more often, sometimes with weight gain
Social withdrawal: Cancelling plans, staying in, and spending less time with people
Irritability: Feeling short-tempered or easily frustrated, even with the people closest to you
Notice that several of these look like hibernation. Sleeping more, eating more, and pulling away from others can feel like your body is trying to wait out the winter. The trouble is that each of these habits also feeds the others. Less contact with friends lowers your mood, a lower mood saps your energy, and low energy makes the next invitation harder to accept.
The cycle can run the other way, too. Say yes to one plan, and that small lift in your mood makes the next yes a little easier. Finding that first yes can be part of what we work on in counselling for depression.
Depression doesn’t always look like sadness. It can feel like exhaustion, irritability, or going through the motions. Explore depression therapy at Radcliffe Psychotherapy Clinic.
Seasonal Affective Disorder Causes
Scientists haven't pinned down a single cause of SAD, but research from the National Institute of Mental Health points to a few connected factors:
Shorter daylight hours: Your brain uses light to set its internal clock, called the circadian rhythm. Less light in winter can throw that clock off, which affects sleep, energy, and mood.
Changes in melatonin: Melatonin is the hormone that helps you feel sleepy. Darkness increases melatonin production, and people with winter-pattern SAD may produce too much of it, which can lead to oversleeping and grogginess.
Lower vitamin D: Your body makes vitamin D when sunlight hits your skin. With less sun, levels can drop. Vitamin D is believed to support serotonin, a brain chemical linked to mood.
All three point back to one thing: light. Less of it throws off your body clock, pushes melatonin and vitamin D in the wrong direction, and leaves your mood with less fuel to run on. The Canadian Psychological Association notes that Canadians are especially at risk because we get so little sunlight in winter.
But your body chemistry isn’t the entire story. Researchers don't yet know whether negative thoughts about winter cause SAD or follow from it, but thoughts and habits are a useful focus in therapy.
Canadians are especially at risk for SAD because of how little sunlight we get in winter.
How Is SAD Diagnosed?
SAD is diagnosed by a doctor or mental health professional through an assessment of your symptoms and their timing. There's no blood test or scan for it. Instead, a clinician looks at how you've felt across seasons and whether the pattern repeats.
Expect questions about when your symptoms usually start and end, how they affect work and relationships, and whether you've had periods of depression at other times of year. A doctor may also check for physical causes that can look like depression, such as thyroid changes. Generally, the seasonal pattern needs to show up for at least two years in a row before it's described as SAD.
Keeping notes beforehand can help during your appointment, so jot down when your energy dips, when you start cancelling plans, and when you notice your mood starting to lift again. Bringing that record gives your doctor or therapist a clearer picture than memory alone.
How to Cope With SAD During Canadian Winters
Small, consistent habits may help with mild SAD symptoms. They work best when you start them early, before the darkest weeks arrive. If your symptoms are stronger, the next section explores professional treatment options.
Get outside during daylight: The CPA notes that sunlight within an hour of waking can help, which is tricky when a December sunrise in Toronto comes close to 8:00 a.m. So catch the earliest light you can: take your coffee to the brightest window, or walk the last stretch of your commute once the sun is up. Then use your lunch break. UBC psychiatrist Dr. Raymond Lam, who has studied seasonal depression for decades, recommends a midday walk in winter because it pairs exercise with outdoor light.
Keep a consistent wake time: Your body clock relies on routine. Waking up at the same time every day, weekends included, gives your circadian rhythm a steady anchor when daylight can't.
Stay physically active: Movement supports mood and energy. Pick something you'll do in February, not only in October. A 20-minute walk you'll repeat beats an ambitious workout plan you'll drop because it’s too taxing.
Plan activities ahead: Low mood makes it hard to decide in the moment. Booking a weekly dinner, class, or game in advance means the choice is already made on the days your motivation is low.
Stay connected with family and friends: Withdrawal feels comforting but tends to deepen low mood. Tell one or two people what winter is like for you, so they can check in when you go quiet.
These habits draw on a therapy approach called behavioural activation, and the idea is simple: you don't wait to feel motivated before acting, because acting is often what brings the motivation back.
If you'd like help building a winter plan that fits your life, our team is here to talk it through with you.
Seasonal Affective Disorder Treatments
The main seasonal affective disorder treatments each tackle a different piece of the challenge. Light therapy helps reset your body clock, medication supports brain chemistry, and psychotherapy takes on the thoughts and habits winter knocks off course. Many people combine them, depending on their symptoms and what has helped before.
Light Therapy
Light therapy means sitting near a special light box for a set time each day, usually in the morning. A review of bright light therapy describes it as a first-line treatment for SAD, and the CPA says that sessions often run about 30 minutes a day. Morning light outdoors helps for the same reason: it signals to your body clock that the day has started.
Talk with your doctor before you begin. Your family doctor can assess whether your symptoms fit SAD and help you choose a lamp, timing, and session length. Tell them about any medications, eye conditions, or past periods of unusually high mood or reduced need for sleep, because these can change the advice and monitoring you need.
Medication
For moderate to severe or recurring SAD, a doctor may suggest antidepressant medication. Some people start medication in the fall, before symptoms usually begin. Medication is prescribed and monitored by a doctor, and it's often combined with therapy.
Psychotherapy
Therapy helps you understand what happens in your mind and routines as the days shorten. Your therapist can help you spot thought patterns that perpetuate symptoms, like "there's no point making plans until spring," and build routines that keep your energy and mood steadier.
Cognitive behavioural therapy (CBT) is the psychotherapy most often recommended for SAD. It works on two fronts at once. On the thinking side, you learn to catch winter’s gloomy predictions, like “I’ll be miserable if I go out tonight,” and check them against how the evening actually goes. More often than not, reality turns out kinder than the forecast. On the behaviour side, your therapist will support you in scheduling small, enjoyable activities before motivation shows up, which pushes back against the urge to hibernate.
The skills are yours to keep. Light therapy is usually used daily from fall to spring, and symptoms may return if you stop early. CBT skills work differently. They can come with you into every fall that follows. Since SAD usually returns on schedule, you can spot your early warning signs and have a plan ready.
Cognitive behavioural therapy is the psychotherapy most often recommended for SAD.
How Therapy Can Help
At Radcliffe Psychotherapy Clinic, therapy for SAD starts with understanding your pattern, either in person at our Toronto office or online. We look at when your symptoms usually begin, which situations make the darker months harder, and what the earliest warning signs are. For one person, the first sign might be skipping the gym. For another, it's snapping at a partner over small things.
From there, we build a plan for the winter months. That might include a morning routine, a short list of activities that tend to lift your mood, and ways to challenge the thoughts that keep you stuck indoors. We also work alongside your doctor's recommendations, so the physical and psychological sides of SAD are both addressed.
Over time, the goal is for you to see the season coming and meet it on your own terms, with a plan you built and skills you trust. When you’re ready, you can learn more about our depression therapy in Toronto and reach out at your own pace.
Frequently Asked Questions
How to treat seasonal affective disorder?
Treatment usually involves one or more options, such as light therapy, psychotherapy, antidepressant medication, and, in some cases, vitamin D. Many people combine a few of these. A doctor or therapist can help you decide which fit your symptoms and history.
How long can seasonal affective disorder last?
For most people with the winter pattern, symptoms last about four to five months, often from late fall until spring. Without support, the pattern can return each year. Starting treatment or coping strategies early in the fall may reduce how long and how hard the low period hits.
What are the symptoms of seasonal affective disorder?
Common signs include a low mood most days, losing interest in things you enjoy, sleeping more but feeling tired, craving carbohydrates, pulling away from people, and feeling irritable. The key clue is timing. If these changes return around the same season each year, it's worth raising with a professional.
Is SAD a real disorder?
Yes. Clinicians recognize SAD as a type of depression with a seasonal pattern. It's different from simply disliking winter, because the symptoms affect sleep, energy, relationships, and daily functioning. If you've wondered whether your winter blues are "just in your head," that question alone is a good reason to reach out to your doctor or a therapist.
Disclaimer: This content is for educational and informational purposes only and is not medical, psychiatric, or psychological advice. It does not replace professional care, diagnosis, or a client-provider relationship—always consult a qualified healthcare provider regarding any health condition or treatment
