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What is seasonal affective disorder (SAD)?

Personal · Oct 20, 2020

By Dylan Zambrano, Mental Health Therapist, Akira by TELUS Health, and Mary Polychronas, Psychologist

 The seasonal change from summer to fall can have a negative impact on our moods, but feeling sluggish, sad, irritable, unmotivated or just generally out of sorts during the fall and winter every year may indicate seasonal depression, also known as Seasonal Affective Disorder (SAD). This year, the ongoing stress and uncertainty caused by the COVID-19 pandemic are likely to exacerbate these seasonal symptoms.


  • About 2 – 6 percent of Canadians will experience SAD in their lifetime

  • Women are up to eight times more likely than men to report having SAD

  • People in northern countries are more likely to experience SAD than those who live closer to the equator

  • SAD tends to run in families — most individuals with SAD have at least one close relative with a history of depression

  • The prevalence of SAD is two times higher in North America than Europe

  • Most people who develop SAD start experiencing symptoms in their 30s

  • An estimated 10 – 20 percent of all mood disorders follow a seasonal course

Seasonal depression is a mood disorder that reoccurs at the same time each year. The most recognizable trait of SAD is the onset and remission of the depressive episodes: SAD typically begins in the fall or winter and ends around spring or early summer.

Unfortunately, with this year’s seasonal change coinciding with an already-difficult period of life for most Canadians, some may experience greater irritability, sleep difficulties, fatigue and a lack of motivation this fall and winter.

SAD symptoms

To be diagnosed with SAD, an individual must meet the criteria for major depression during a specific season at least two years in a row. According to the DSM-V (Diagnostic and Statistical Manual of Mental Disorders, 5th Edition), five or more of the following symptoms must be present, representing a change in one’s ability to function. One of the symptoms must include either i) depressed mood or ii) loss of interest or pleasure in preferred activities:

  • Depressed mood (sadness, emptiness, hopeless)

  • Diminished interest or pleasure in preferred activities

  • Significant weight loss (without dieting) or significant weight gain

  • Insomnia or hypersomnia

  • Psychomotor agitation or retardation (restlessness or being slowed down)

  • Fatigue or loss of energy

  • Feelings of worthlessness or excessive or inappropriate guilt

  • Difficulties concentrating or making decisions

  • Recurrent thoughts of death, or suicidal ideation with or without a plan

Symptoms often cause distress and may affect work, relationships and other important areas of one’s life. It is important to note that, although SAD is not common in children and adolescents, symptoms for those age groups may differ and include irritable mood rather than sadness.

What causes SAD?

  1. Temperament:

    SAD often affects those with high levels of negative affectivity

  2. Environment:

    Environmental triggers may include adverse childhood experiences and stressful life events, such as the COVID-19 pandemic

  3. Genetics and Physiology Factors:

    Hereditary factors increase the probability of major depressive episodes, and pre-existing mood and non-mood disorders, including substance abuse, personality disorders and anxiety, are also a determining factor.

Treatment options

Individuals with moderate to severe SAD may often choose to remain “stuck” as the thought of taking action to treat the disorder may increase anxiety. To prevent this, it is important to proactively develop regular, healthy habits and routines that increase our overall wellbeing – and are also known to diminish the effects of SAD.

Establishing such routines early in the fall will help us become better-equipped to adapt to our current pandemic circumstances — especially during the winter months.

Examples of activities to include in your fall and winter routine include: maintaining social connections while adhering to current safety protocols, exercising and eating healthfully, engaging in self-care techniques, practicing relaxation techniques like meditation or yoga, making time for activities or hobbies that evoke a sense of joy and fulfillment, spending time outdoors and increasing exposure to sunlight, and developing a gratitude practice.

If you think you might have SAD, contact your primary healthcare provider or connect with a healthcare professional through Akira by TELUS Health. Treatments may vary from person to person, and may include:

  • Cognitive Behavioral Therapy (CBT), a form of psychotherapy that helps individuals channel thoughts and behaviours in a way that can decrease the intensity and duration of SAD.

  • Phototherapy, which suppresses the brain’s secretion of melatonin through high-intensity daily light exposure.

  • Pharmacotherapy, such as with antidepressant drugs that may prove effective in reducing or eliminating symptoms.

Since SAD typically recurs around the same time each year, proactive, preventive measures can reduce its symptoms as well as their intensity and duration. When the depressive episode is treated effectively, the symptoms may fully subside.