Norman Rosenthal has written extensively in the area of Seasonal Affective Disorder (SAD).
His most recent book, “The Winter Blues” (fourth edition) is an excellent summary of the research on SAD. According to Rosenthal, about 9 percent of the adult population in our northern latitude experience symptoms of SAD compared to only about 1.5 percent of people in Florida.
He stated that one of three people in Scandinavian countries may have SAD. Symptoms often begin at adolescence; thus, many people with SAD have pleasant childhood memories of winter. The research shows that the hormone melatonin, which increases during nighttime hours, may be critical in those who have SAD.
Rosenthal encourages us to notice that if we have repeated symptoms during the winter months, especially during December, January and February; although symptoms may occur as early as October. Although changes in your mood during the winter months may be indicative of SAD, it may also be a medical problem such as hypoglycemia, viruses such as Epstein-Barr or hypothyroidism. Therefore, if you have these symptoms you should consult with your physician.
In one study, participants had experienced an average of 13 winters with seasonal symptoms without receiving treatment. Depression is more than just sadness. Symptoms often begin with physical problems such as fatigue, loss of energy, lowered sex drive, increase or decrease in appetite, and increased need for sleep. Also, cognitive problems such as trouble with memory and concentration, and difficulty making decisions can occur.
Depression also includes emotional components such as sadness and irritability, problems such as difficulty enjoying life, feelings of worthlessness and inappropriate guilt, as well as suicidal thoughts or attempts. It is not uncommon to have an increase in cravings for simple carbohydrates and experience significant weight gain. Women may also have more difficulty with premenstrual dysphoric disorder during the winter months.