For some people, that can be a serious problem, known as Seasonal Affective Disorder, or SAD for short. But there is help available.
The Early Show co-anchor Harry Smith spoke with Dr. Michael Terman, who has perfected the use of light therapy for people affected by Seasonal Affective Disorder.
Terman is also president of the Center for Environmental Therapeutics, a non-profit professional agency that fosters research and education in the field of non-pharmaceutical treatments for depressive and sleep disorders.
Terman says Seasonal Affective is a major public health problem. At the tip of the iceberg, there are people suffering from clinical depression, and then somewhere toward the bottom are people who are just dragging, not getting their work done, and are just unhappy.
Problems usually set in gradually in the fall, Terman explains. People feel sluggish, have a need for more sleep, have trouble getting out of bed, and crave carbohydrates. Then, depression hits.
To be affected be SAD, you need to have genetic vulnerabilities to becoming depressed and to the change in the seasons.
The most severe group earns a psychiatric diagnosis of major depression each year. The other group gets what Terman calls the doldrums. Both groups respond very well to light therapy.
"You might guess that someone with full-blown SAD would need more light, but they don't," Terman says. Both groups respond very well to the same amount of light therapy: about a half hour a day.
You just set a "light box" on a desk or table. The treatment regimen is very well-honed. "We did clinical trials at Columbia," Terman says. "By delivering an outdoor level of light, we can get complete remission of these symptoms within days with as little as 30 minutes in the morning.
"The key is that we are resetting the internal biological clock. That clock begins to run late as the sunrise gets later and later. We're pulsing the internal clock with light. It's all about the morning for the vast majority of people. The appropriate time of the morning will differ from person to person.
"What we have done is developed an automated questionnaire on the Web, at cet.org. The questionnaire feeds back the optimum time that would be the best light therapy for each person. I recommend that people go online, do the questionnaire and then bring the results to their doctor."
Terman tells Smith that 80 percent of people who use light therapy alone get better. The key is to know when to do the light therapy.
Read a transcript of a Healthology presentation on S.A.D., featuring Terman.