Since she was a child, “Francine,” a 35-year-old lawyer, knew that she craved sunshine but she never knew why. She was a fair-skinned, blue-eyed blonde who realized that sun exposure could be dangerous and promote melanomas. But there was never enough light in the winter for her, and it made her feel out of sorts.
She and her family lived in New York City. Sometimes in the winter she’d be able to take a vacation in Florida or the Caribbean. To escape the heat every summer, her parents rented a house on Long Island. She loved going there with her two brothers, and she’d try to spend every weekend at the house with her parents.
Last winter was brutal for her. It was dark and dreary, with a lot of rain and snow. Francine was confined to the city without any vacations. She retreated into herself. To make matters worse, her workload was so heavy she had to endure 12-hour weekdays and work on the weekend as well. By December she found she could not wake up in the morning. She had to drag herself out of bed and force herself into the shower. When she had a weekend off, she slept it away. She found she could never get enough sleep even if she stayed in bed 15 hours.
Francine also craved carbohydrates. She ate more bread and pasta than ever before and wound up gaining 10 pounds. Not only was this extra weight burdensome, she also had no energy and couldn’t concentrate on her work. She withdrew from her friends and family and tried to struggle through the days. She didn’t want to admit it, but she felt downright depressed.
When April arrived, she celebrated spring by sitting out in the sun every day at lunch time. After one week, she felt so much better. The sunshine she craved was back. She was able to wake up in the morning and feel refreshed after six to seven hours of sleep. Her appetite decreased back to normal. Instead of a lot of starches, she started eating salads and fresh fruits. Her concentration returned, and she churned out one brief after another, as she had in the past. She was happy to feel re-energized. Her parents opened up their summer house in May, and Francine went there every weekend. Before long she’d lost the extra 10 pounds. She socialized with friends again, and even found a summer romance.
Her new boyfriend, Howard, a psychologist, told her she probably had seasonal affective disorder, or SAD. He explained that if she had depression in the winter which relented in the spring and summer, and “the depression had lasted for two years with no nonseasonal major depressive episodes during that period,” then she had SAD.
In the United States SAD affects from 1.5 percent of adults in Florida to nearly 10 percent of adults in Alaska. Although it is not listed as a unique mood disorder in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV or DSM-V) because psychiatrists were initially skeptical of its existence, it has gained more acceptance, and is listed as a “seasonal pattern” specifier for recurrent major depressive disorder.
SAD is related to light. The pineal gland in the brain produces melatonin in the dark, which helps people sleep. However, in some individuals, too much melatonin is produced, and it can lead to depression and SAD. SAD sufferers may also have low serotonin levels — antidepressants that replenish serotonin have been shown to help eliminate depression in SAD patients. Seasonal affective disorder is caused by a disturbance in the normal circadian rhythm of the body. Light entering our eyes regulates the rhythm. Nowadays, our natural rhythms are thrown off anyway, because we are subject to so much artificial light.
In primitive times, human beings were synchronized with sunrise and sunset. We rose at sunrise and went to bed at sunset. In modern times, we keep our own schedules, which often have nothing to do with natural patterns of light and dark. In the past, winter was a time when many human beings would basically hibernate like other animals. There was less food available in the winter, so hibernation was appropriate. Depression, oversleeping, and overeating would be useful to hibernators. Perhaps people with SAD allowed our species to survive better, so their genes were passed on.
Many people with SAD use light boxes that produce 10,000 lux to tide them over through dark winters. (The U.S. Food and Drug Administration has not approved light boxes to treat SAD, because the clinical trials did not definitely prove that light boxes work.) Since light leads to less melatonin and less depression, another treatment for SAD is to take frequent trips to sunny climes like Florida or Mexico.
Francine, who was allergic to many medicines, was glad she didn’t have to resort to antidepressants to return to normal. On the advice of her boyfriend, she bought a light box to prepare for the following winter. In the meantime, she went out to enjoy the sunshine.