Feeling sad or hopeless, sleepier than usual and lacking energy in recent weeks? These mood changes could be a sign of seasonal affective disorder (SAD) — a type of depression that recurs each year for about four to five months, most often beginning when the days get shorter in the fall and ending when longer hours of daylight return in the spring and summer.
Sometimes called “winter blues,” the seasonal depression affects about 5 percent of the U.S. population and afflicts women far more often than men, according to the nonprofit group Mental Health America. In some regions, however, the tally is considerably higher. In general, the farther you live from the equator, the greater your risk for winter blues.
Health experts generally agree that reduced levels of sunlight in fall and winter months can lead to changes in body chemicals — lowering levels of serotonin, which has been linked to depression, and increasing levels of melatonin, which affects the body’s internal clock and can lead to sleepiness. Other symptoms of SAD include carbohydrate craving, an increase in appetite overall and weight gain. Treatment for SAD varies, depending on the severity of the condition and its effect on one’s daily life. Treatment frequently includes light therapy — sitting in front of a very bright light box for about 45 minutes a day — and may also entail talk therapy and antidepressant medication.
Although the winter disorder is by far the most common type of SAD, some people experience the mood changes of seasonal depression in the spring and summer months known as summer-pattern SAD or summer depression.
This article is part of The Post’s “Big Number” series, which takes a brief look at the statistical aspect of health issues. Additional information and relevant research are available through the hyperlinks.