Light therapy is one of the tools increasingly used to combat the seasonal affective disorder many of us face during winter months. Marie-Pier Lavoie, a psychologist specializing in seasonal depression and member of the Ordre des psychologues du Québec, explains how this method offers multiple benefits in cases of low morale.
What is Seasonal Affective Disorder (SAD)?
Seasonal depression is a set of depressive symptoms that usually occurs in the fall and winter and gets resolved naturally in the spring.
What are the signs?
The most common symptoms are fatigue, low morale and decreased interest in daily activities. There are also “atypical” symptoms that are different from “standard” depression, such as increased appetite ― especially for starches and sugars ― and excessive daytime sleepiness. It's a bit as if the person wants to hibernate. Usually there is a spontaneous, natural remission in the spring unlike with classic depression.
Has the Covid-19 pandemic accentuated the phenomenon this year?
It is difficult to assess the impact of Covid-19 on SAD symptoms. Of course the pandemic has affected our daily lives in many ways. For those working from home and with more free time, the possibility to go outside could be beneficial for symptoms as it could be possible to take advantage of the natural light.
How can bright light therapy help fight this seasonal disorder?
Bright light therapy is the scientifically recognised treatment of choice for treating winter SAD. The light entering the eye influences the brain to stop the production of melatonin ― which causes drowsiness ― and to produce more serotonin, a neurotransmitter involved in appetite and mood.
Has this treatment become the standard in some countries?
I don't know about current use of light therapy on a global basis, but the Nordic countries were among the first to use light therapy in public places and in the workplace. In Quebec, use of bright light therapy is common, and for several years now, the population has become more aware of the effects of changing light levels in the fall.
Are the lamps that can be bought in stores really effective?
It all depends on the lamp's features. Currently scientists agree that the lamps must diffuse 10,000 lux of light intensity, produce white light ― bluish LED lamps should be avoided ― and have a wide enough light field so that the treatment is as effective as possible. Concerning the instructions for use, one should stand 30 cm from the lamp as soon as one gets up, keep one's eyes open and expose oneself to the light for 30 minutes. It is possible to perform an activity at the same time, whether it is eating breakfast, reading a book or using the computer. The lamp can then be placed at a 45-degree angle. What is important is that the light reaches the eyes.
Are there potential dangers depending on how these lamps are used?
LED lamps can be harmful to the retina of the eye in the long term. Therefore, it is preferable to use white light that has not shown any long-term damaging effects. If light therapy is used for too long, for example one hour rather than 30 minutes a day, or in the evening rather than during the day, you may experience restlessness and difficulty sleeping. As for side effects, some people will experience mild headaches, dry eyes or restlessness. In such cases, it is sufficient to move the lamp back or to reduce exposure time.
Are there other methods that can be used to combat Seasonal Affective Disorder (SAD)?
Of course! Several studies show the benefits of physical activity on depressive symptoms, and when you can get outside it's even better! Adopting good eating habits can also help in order to have enough energy. Continuing as much as possible to have a social network ― whether online or not in times of pandemic ― is essential, as is having fun and rewarding activities to do every day.