Seasonal Affective Disorder

We all know how the weather affects what we wear, how we travel, what we choose to do, and how we feel. However, when weather affects us to such an extent that we begin to have trouble functioning as usual, this can become more than just a case of the "winter blahs", according to the Canadian Mental Health Association.

Seasonal affective disorder, or SAD, is a type of clinical depression that appears at certain times of the year. It usually starts with the shortening days of late autumn and lasts through the winter. However, the term "winter blahs" can be misleading; some people have a rarer form of SAD which is summer depression. This condition usually begins in late spring or early summer.

Since the days of winter get shorter the further north you go, SAD has been found to be more common in northern countries. In Canada, about 2 to 3% of the general population will experience SAD in their lifetime. Another 15% of Canadians will experience a milder form of SAD where they simply have the "winter blues".

SAD can be debilitating, preventing healthy people from functioning fully. It may affect their personal and professional lives and seriously limit their potential. Many people may be suffering unnecessarily -- unaware that SAD exists or that help is available.

When a person is going through an episode of SAD, their symptoms may be similar to those of a person going through a depressive episode. This can make it difficult to diagnose. Even physical conditions, such as thyroid problems, can look like SAD. One of the most common symptoms of SAD is a change in appetite. Often, the person gets cravings for sweet, starchy, or other carbohydrate-rich foods. This can result in overeating and weight gain. People with SAD are often tired all the time, tend to oversleep, and can sometimes feel anxious and desolate as well. Some people may even have suicidal thoughts.

Although SAD may affect some children and teenagers, it tends to begin in people over the age of 20. The good news is that the risk of SAD decreases with age. Like some other depressive disorders, SAD is more common in women than in men.

Remember that self-diagnosis or treatment of SAD is not recommended because there are other medical causes for depressive symptoms, and because light therapy may be harmful to people with certain medical conditions (for example eye disease). See your doctor first.

Research on SAD is still in its early stages. However, it is likely that SAD may be caused by a lack of daylight. Each of us has an internal "biological clock" that regulates our routines, a wake-sleep and active-inactive cyclical routine called a circadian rhythm. This biological clock responds to changes in season, partly because of the differences in the length of the day. For many thousands of years, the cycle of human life revolved around the daily cycle of light and dark. We were alert when the sun shone; we slept when our world was in darkness. The relatively recent introduction of electricity has relieved us of the need to be active mostly in the daylight hours. But our biological clocks may still be telling our bodies to sleep as the days shorten. This puts us out of step with our daily schedules, which no longer change according to the seasons.

One useful way to combat SAD is to use light therapy, also known as phototherapy. This can be done using a fluorescent light box, a device now available in a variety of safe, economical and portable designs. What they all have in common is they all give out bright, artificial rays that mimic sunlight.

People with seasonal depression during the wintertime report significant relief after using the light box for about 30 minutes a day. Although phototherapy can produce side effects, these are usually mild experiences of nausea, headaches, eye strains or feelings of edginess that go away after using the lightbox for some time. However, people with certain medical conditions or who are taking certain medications should have special eye examinations before considering light therapy.

Leaving SAD symptoms unchecked can spell disaster for other medical/mental health conditions. The light device is only part of a larger wellness plan. Healthy lifestyle changes like exercise, relaxation, healthy diet, social supports, medical supports, and compliance with medications, all can make a difference.

Tips to Ease your Symptoms

The following suggestions may help ease or even prevent SAD symptoms from becoming debilitating or be helpful by themselves for those of us with mild symptoms of the "winter blues":

Advice on Light Devices

Although light therapy is effective for SAD, researchers still do not fully understand how the light works and what is the best method for light therapy. There are now many light therapy devices available on the market making claims about light treatment, but light therapy devices are not well regulated in Canada. Therefore, it's wise to be cautious about recommending light therapy devices and think about the following four principles:

  1. the light device should be tested and found effective in scientifically-valid studies
  2. the light device should have a filter that blocks harmful ultraviolet rays
  3. the light device should be CSA approved for use in Canada (UL means approved for use in the US)
  4. the light device company should have a track record of reliability

Fluorescent light boxes are recommended because they have been extensively tested with the greatest evidence for effectiveness in scientific studies. Other light devices, for example light visors and dawn simulators, may be beneficial for some patients but there is less evidence for effectiveness compared to light boxes. For a list of stores and companies that sell light boxes throughout BC and Canada, visit www.psychiatry.ubc.ca/ mood/sad