The shorter, darker days of winter can be a hard adjustment for some. For the estimated 10 million people in the United States who suffer from a medically recognized condition called seasonal affective disorder (SAD), it’s even more difficult.

SAD is a type of depression that’s related to changes in seasons — it begins and ends at about the same time every year and is due to the lack of sunlight and changes in the day–night cycle.

Sometimes referred to as winter depression or winter blues, SAD is a mood disorder in which people with normal mental health throughout the rest of the year experience depressive symptoms in the winter. In a much less common variant, people suffer from summer depression or sadness.

SAD is more prevalent in northern locations. In Florida about 1 percent of the population is affected, while in Alaska and New Hampshire about 10 percent is.

Recognize the symptoms:

• Lack of energy, fatigue, moodiness;
• Craving starches, sweets and “comfort” foods, which at first provide an energy boost but then lead to a crash, setting the stage for the cycle to begin again;
• Social withdrawal;
• Loss of interest in exercise and other activities usually found enjoyable;
• Sleeping more;
• Craving sunlight;
• Heightened anxiety as a result of spending more time indoors and less time outdoors.

Treatment:

• Prioritize getting outside on sunny days as much as possible — go for a morning walk;
• Bright light therapy — light boxes, lamps and visors — can help. Ask your doctor to recommend light therapy with white (not blue) fluorescent bulbs that filter out UV light. Do not use tanning beds as a treatment.
• If SAD is interfering with daily functioning, seek professional mental help;
• Schedule a vacation to a warm, sunny place;
• Avoid simple carbohydrates; replace with whole grains and legumes, nuts and healthy, high-protein foods;
• Continue your daily routine — stay active and don’t forget to exercise; and
• Stay in touch with family and friends — maintain your social connections.

The good news is that starting on the winter solstice (Dec. 21), the days get longer each day and the nights get shorter. Much as our ancient human ancestors did, we can all celebrate the return of the sun.

Visit SAD for additional resources.