"There are a few differences in the symptoms--for instance in typical depression, people note a decrease or loss of appetite and frequently have difficulty sleeping. With seasonal depression, there is typically an increase in appetite, particularly for carbohydrates, and oversleeping."

Fatigue, avoiding social situations, increased appetite and weight gain, oversleeping, loss of energy and motivation, irritability and sometimes relationship difficulties, along with a depressed mood are common SAD symptoms.

"It is estimated that about four to six percent of the general population experience winter depression and another 10 to 20 percent experience what is often called 'winter blues,' meaning that they have milder symptoms. Women outnumber men by about four to one, and the average age of onset is in the early 20s.

"While it appears that winter depression is more common in the northern latitudes, a group of people experience a summer pattern, which appears to be more similar to typical symptoms of depression with decreased sleep, weight loss, and poor appetite. There is another group who may experience increased energy and symptoms approaching mania. This may be more common in those who have been diagnosed with bipolar or manic-depressive disorders, Blum says.

One of the most successful treatments has been the use of light therapy using special lights at an intensity of 10,000 lux directed toward the person. However, it is not necessary to stare directly at the light source, Blum says. The light source is commonly a fluorescent light fixture with screens that eliminate ultraviolet light, but there are also some newer units that use LEDs as the light source and seem to work with shorter periods of exposure.

Blum says some people may have only a partial response to light therapy, and it may be necessary to add antidepressant medication or to increase the dose if someone is already on medication. Those people who have a milder form of seasonal changes may find that some simple changes in lifestyle such as getting out for a 30 minute walk outdoors each day, increasing the available light in their homes and workplace, and managing stress during the winter months may be enough to make a difference.

If there has been a consistent pattern of SAD for two years or more, it is likely to continue.

"If you think you suffer from SAD, I suggest first trying some self-help measures that I mentioned previously, particularly getting outdoors for a daily walk during daylight and increasing the amount of light in the indoor environment. If, despite this, the symptoms are interfering with normal activities, it is time to consult a psychiatrist with experience in treating seasonal affective disorder," Blum says.

For more information:

SAD

What Is SAD?