Some 2% to 6% of Canadians suffer from Seasonal Affective Disorder (SAD). This “depressive” disorder generally occurs in autumn or winter, when natural light is scarcer. Various studies have demonstrated the effectiveness of light therapy in treating this disorder.

In our article, find out more about the causes and symptoms of SAD and how light therapy can help. If your symptoms are too much to bear, talk to your doctor about a solution.

What is Seasonal Affective Disorder (SAD)?

SAD, also known as “recurrent winter depression”, is a form of depression related to the degree of exposure to sunlight, which intensifies in most people in autumn and winter. If you’ve been suffering from periodic depression for more than 2 years, and your symptoms recur at the same time every year, you may have SAD.

Who is most at risk of SAD?

SAD is a real medical condition that can affect anyone. However, some people are more likely to be affected by it:

  • Women of childbearing age are more affected than men.
  • For most SAD sufferers, symptoms appear between the ages of 18 and 30.
  • People with a history of depression.
  • People living in northern countries, where days are shorter during the winter months. Their symptoms begin to diminish with the arrival of spring, as the days lengthen.

What are the symptoms of SAD?

People with SAD feel tired and lethargic, and may seek to avoid the company of family and friends. Other symptoms of SAD include:

  • Inability to concentrate
  • Sadness or despair
  • Increased appetite and craving for sweet or starchy foods, accompanied by weight gain (usually during winter)
  • Irritability,
  • Increased drowsiness or sleep disorders
  • Decreased energy
  • Decreased libido
  • Decreased interest in work and social activities.

Many of the symptoms of SAD resemble those of major depression. Talk to your doctor if you experience any or all of the above symptoms.

Light therapy treatment

Several treatments are currently available to help SAD sufferers. Light therapy remains an effective, practical and affordable solution.

What is light therapy?

Light therapy is a treatment involving exposure to a high-intensity artificial light source designed to simulate daylight. Daily exposure to bright light can help restore the balance of brain chemicals and the body’s rhythm.

Which light therapy lamp should I use?

light therapy

Light therapy is easy to perform in the comfort of your own home. Available light sources include light boxes, desk lamps, helmets with light visors or lamps worn on the head.

White fluorescent light is safer than ultraviolet light. Most light therapies are recommended at an intensity of 10,000 lux (unit of measurement for light intensity).

How long do I need to be exposed?

To feel the benefits of light therapy, a daily session of at least 30 minutes is recommended (for a 10,000 lux lamp). Most patients have their session in the morning, as evening sessions can disrupt sleep. The duration of exposure may vary according to the power of the lamp and the distance between you and the source. It may therefore be useful to extend the session to 1 or 2 hours.

Results are not instantaneous, but may take a few days or weeks to appear. It can take from 2 to 4 weeks for SAD symptoms to diminish with light therapy.

What are the side effects of light therapy?

Few people experience side effects. However, some people have experienced headaches, nausea or eyestrain. If any of these symptoms bother you, talk to a healthcare professional.

Other treatments for SAD

For people with severe symptoms for whom light therapy is not enough, other solutions may be used, alone or in combination:

  • Medication and antidepressants for severe cases of SAD
  • Counselling and follow-up by a therapist
  • Complementary treatments and therapies

If SAD affects you and your mental and physical health, the advice of a healthcare professional may be important.

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