Seasonal affective disorder (2)

For some, winter is consistently associated with low energy and motivation, depressed mood and increased appetite. This is known as seasonal affective disorder (SAD) and those who experience it tend to get recurring depression during fall and winter months with normal mood returning during the spring and summer.

Typically, January and February are the most difficult months for individuals experiencing SAD, but for many, symptoms begin as early as October and can last until May.

Symptoms in SAD are the same as the usual symptoms of depression, feelings of sadness, changes in appetite and sleep pattern, loss of interest in activities, decreased libido and social withdrawal.

Atypical symptoms, increased vs. decreased appetite, increased vs. decreased sleep, are more common in SAD than in other types of depression. In order for seasonal depression to be diagnosed, symptoms must be consistently associated with a season (usually winter) and fully dissipate during the spring and summer months. Usually, SAD involves mild to moderate symptoms that do not require hospitalization, but in some cases the depression can be severe.

Although seasonal variations in light are thought to be involved in SAD, there is also likely a genetic component to this condition. Many people with seasonal depression have a family history of psychiatric illness, usually depression. SAD has been shown to be more frequent as one moves from south to north, the prevalence being about 1% in Florida and 9% in southern Canada.

Light therapy is a first line treatment for seasonal affective disorder and has been shown to be very effective in clinical trials. In this therapy, patients receive a phototherapy lamp with a bulb emitting a colour temperature somewhere between 3,000 and 6,500 degrees Kelvin. The bulb is encased in a box with a diffusing lens that filters out the potentially harmful UV radiation. Patients then spend certain amounts of time (usually between 30-60 minutes) each day sitting with the lamp turned on at eye level.

The amount of time each person needs to be exposed to the therapeutic light will depend on the severity of the depression and the intensity of the light and should be prescribed by a physician. About 5,000 lux hours of exposure are required. This could be 10,000 lux for 30 minutes or 5,000 lux for 60 minutes. There are several different models of light available locally and they can also be rented at some pharmacies or medical equipment stores.

It is the light entering the eyes that is important. Tanning beds are not effective for this purpose since they expose the skin and not the eyes. Studies show this therapy leads to full remission in 50 to 80 percent of those who use it throughout the winter months. In cases where phototherapy doesn’t work, an antidepressant medication may prove effective either on its own or in combination with the light exposure.

Antidepressants are effective both in treating the depression and in preventing it, if they are taken all year round. Bupropion is particularly well suited for most patients with SAD since it is somewhat energizing and does not increase appetite. These patients are typically eating and sleeping excessively and have profound lack of energy and motivation.

For mild symptoms, spending time outdoors during the day or increasing the amount of sunlight exposure through windows can be helpful. In fact, one study found that an hour long walk in winter sunlight was just as effective as two and a half hours under bright artificial light. In the Okanagan Valley which is often socked in during the winter months, I encourage people to take a drive on cloudy days and try to get above the clouds. A winter vacation to a sunny location can also be helpful.

Most depressions are recurrent and can be prevented by taking a medication that has proven effective, on a continuous basis. When a depression is known to recur every year it is usually best to remain on medication continuously rather than trying to time the medication for each recurrence. Depression is toxic to your brain and antidepressants are neuro-protective.


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