Seasonal Affective Disorder

Seasonal affective disorder (also called SAD) is a type of depression that follows the seasons and is usually called winter depression. It usually begins in late fall or early winter and goes away by summer. SAD may be related to changes in the amount of daylight during different times of the year.

With respect to prevalence, about half a million people in the United States may have winter depression. Another 10% to 20% may experience mild SAD. SAD is more common in women than in men. For adults, the risk of SAD decreases as they get older. SAD is more common in northern geographic regions, where the exposure to bright light is obviously reduced during winter season.

Why does seasonal affective disorder occur?

Seasonal mood variations are believed to be related to light. An argument for this view is the effectiveness of bright light therapy. SAD is measurably present at latitudes in the Arctic region, such as Finland (64º 00´N) where the rate of SAD is 9.5%. Cloud cover may also contribute to the negative effects of SAD.

SAD can be a serious disorder and may require hospitalization. There is also potential risk of suicide in some patients experiencing SAD. One study reports 6-35% of sufferers required hospitalization during one period of illness. The symptoms of SAD mimic those of clinical depression. At times, patients may not feel depressed, but rather have depression equivalent symptoms such as a lack energy to perform everyday activities. Norman Rosenthal, a pioneer in SAD research, has estimated that the prevalence of SAD in the adult United States population is between about 1.5 percent in Florida and about 9 percent in the northern US.

Various causes have been suggested. One possibility is that SAD is related to a lack of serotonin, although this theory has not been widely accepted.

How does my doctor know I have SAD?

1. Appetite changes, especially a craving for sweet or starchy foods
2. Weight gain
3. Heavyness in the arms or legs
4. Decreased energy and fatigue
5. Oversleep need
6. Difficulty concentrating
7. Irritability or excessive passiveness
8. Increased sensitivity to social rejection

According to the American Psychiatric Association, for a diagnosis to qualify as SAD, it must meet four criteria:

I. Depressive episodes at a particular time of the year

II. Remissions or mania/hypomania also at a characteristic time of year

III. These patterns must have lasted two years with no nonseasonal major depressive episodes during that same period

IV. The seasonal depressive episodes outnumber other depressive episodes throughout the patient's lifetime.

Treatment for SAD

Winter depression is probably caused by your body's reaction to a lack of sunlight. Light therapy is one option for treating winter depression. You will need to sit in front of the light box or wear the light visor for a certain length of time each day. Generally, light therapy takes about 30 minutes each day throughout the fall and winter, when you're most likely to be depressed. The sufferer sits a prescribed distance, commonly 30-60 cm, in front of the box with her/his eyes open but not staring at the light source. Many patients use the light box in the morning, however it has not been proven any more effective than any other time of day. Discovering the best schedule is essential because up to 69% of patients find it inconvenient. Dawn simulation has also proven to be more effective in some studies, there is an 83% better response when compared to other bright light therapy

When used properly, light therapy seems to have very few side effects. Side effects may include eyestrain, headache, fatigue, irritability and inability to sleep (if light therapy is used too late in the day).

Tanning beds shouldn't be used to treat SAD. The light sources in tanning beds are high in ultraviolet (UV) rays, which harm both your eyes and your skin.

In addition to the light box your doctor may also want you to try a medicine or behavior therapy to treat your SAD. If light therapy or medicine alone doesn't work, your doctor may want you to use them together.

Please view the following video related to SAD