Studies have also shown that several classes of antidepressants improve SAD symptoms. If one only has depression in the winter, and no other time of the year, antidepressants can be started as a protective measure in the fall before the start of symptoms and stopped again in the spring. Various forms of psychotherapy have also been shown to be effective in treating SAD.
I don't recommend starting any type of medical treatment without first talking with your doctor.
If you are sensitive to winter, there are several other things you can do to help your mood and energy level.
The first seems counterintuitive, and that is to resist the temptation to sleep late or stay in bed on cold, gray mornings.
Even the grayest morning provides many times more light than the typical indoor environment. And light in the morning helps people fall asleep earlier in the evening and to sleep more deeply.
This is important because SAD is tightly associated with something technically known as "phase delay," which means that people with SAD tend to stay up late and sleep late. If you have this behavior, you can improve your mood just by training yourself to move your sleep period forward.
Exercise can also be hugely helpful in combating SAD, especially in the morning. Exercise increases fitness and stimulates the production of antidepressant compounds in the brain and body. Exercising in the morning can also help you fall asleep earlier and sleep better.
I was somewhat unusual in suffering with SAD, because it tends to afflict women more often than men. But I was typical in one fortunate way. SAD is a young person's disease. Many people begin to "outgrow" the condition in their 40s and 50s.
That was the case with me. One winter in my mid-40s the winter blues just didn't happen, and the light box sat unplugged at the back of my desk.
A final note: If you've been thinking to yourself, "I love winters -- summer is what gets me down," let me assure you that you are not alone. Although far less common than winter depression, summer-type SAD is a well-recognized condition. Unlike winter depression, summer depression is all about heat. The hotter it is, the more likely people are to become depressed.
Perhaps because summer depression is so much less common than winter depression, little is known about how to optimally treat it. But I'm put in mind of Mark Twain's comment that the coldest winter he ever spent was a summer in San Francisco, and I suspect that a midsummer journey to a cold, foggy coast might provide tremendous relief.