Winter blues? Keep the lights on

Light therapy helps people with SAD; bad for
the hydro bill but good for the soul

By Janet Forest

For doctors across this country the winter season usually brings with it not only snow, but loads of sick patients piled up in the waiting room. You have to treat everything from the sniffles to bronchitis to broken bones. But there is also something else you should keep your eyes out for. In its most mild form it may mask itself as laziness and at its most severe, depression -- seasonal affective disorder (SAD).

SAD was observed in patients as early at 1845 but it wasn't until 1984 with the publication of the Rosenthal study that doctors identified the disorder and developed specific treatment for this unique form of depression. Studies have confirmed that SAD affects between 6% and 10% of people living in northern parts of North America, which means that you might encounter more than one patient this winter who is suffering from something other than just the winter blues.

SAD occurs during the winter months when daylight hours decrease. The onset of symptoms -- depression, increased sleep, weight gain, carbohydrate cravings -- usually occur between September and November and can last until April. Darkness causes the brain to convert a larger amount of serotonin into melatonin and the secretion of melatonin increases. The insufficient amount of serotonin is what allows the symptoms of SAD to develop. This biochemical imbalance is caused specifically by a deficiency of exposure to sunlight. Light therapy has proven to be up to 85% effective in treating SAD -- either on its own or combined with antidepressants. The treatment requires patients to sit near artificial light boxes that give off a minimum of 10,000 lux (lumens per square metre) for a half hour a day in the morning or both in the morning and the afternoon. Although antidepressants are used in treating SAD, light therapy is a viable alternative for patients with mild to moderate levels of SAD.

The first onset of SAD tends to occur in individuals aged 18-30, which makes the student population very vulnerable. Dr Norman Hoffman of the Mental Health Unit at McGill University, treats about 20 students per year and sees several others who are looking for information on light therapy and self-treatment. Since 2001 the Mental Health Unit has taken steps to make light therapy available to students.

"A significant number of students do have SAD and light therapy is effective. Our service rents out lights for a one- to two-week period so students can determine if they work," says Dr Hoffman. He explains that the advantage of light therapy is that patients can see the improvement in their moods within a few days.

But light therapy is not without its shortcomings. Dr A Missagh Ghadirian, founder of the Clinic for Seasonal Affective Disorder at the Allan Memorial Institute also at McGill, says that light therapy has some side effects like nausea, eyestrain and headache. But these are still significantly fewer than side effects from medications. "Light therapy is more natural and patients are more inclined to use it." He adds that it is also more convenient because patients don't have to go outside in the bitter Canadian cold. They can just sit at their desk with the lamp on while they work.

In addition to the lights they rent out, the McGill Mental Health Unit has also put two lamps in one of the cafeterias located at the downtown campus. "The units at the caf offer students the opportunity to continue treatment, as well as get increased social contact," says Dr Hoffman.

While there is nothing specific that predisposes university students to SAD, light therapy can help some students perform better in winter. Dr Ghadirian explains that a study conducted in Scandinavia, where winter days are extraordinarily short, showed that elementary school students who studied in classrooms flooded with light performed better than those without the extra light. While the study was successful, he adds that some university students might find the extra light irritating.

Dr Ghadirian says that light therapy is ideal for patients with mild to moderate cases of SAD, and is affective in 40-65% of patients. However, there is still another 30-35 % who will not respond to the treatment and light therapy is not sufficient for patients with severe cases. Light therapy technology continues to develop and companies are trying to make the therapy more efficient and decrease the required time spent sitting near the lamps.