As winter approaches, its short dark days can give some people the blues and in others triggers depression, affecting everything from their work to their love lives.
"When the days get shorter and there is less light, people's biological systems naturally slow down, causing them to want to sleep more and crave sweet and starchy foods," said David Miklowitz, a professor of clinical psychology at the University of Colorado at Boulder. "Many people experience this, and it is typically called the winter blues."
People suffering from what's known as seasonal affective disorder, or SAD, slide into what psychologists call an episode of clinical depression. This means their symptoms last more than two weeks and they have great difficulty conducting their normal daily routines, according to Miklowitz, who is director of the Robert D. Sutherland Center for the Evaluation and Treatment of Bipolar Disorder.
Symptoms of SAD can include constant feelings of worthlessness, a lower sex drive, difficulty concentrating or making decisions, feelings of guilt, an increase or decrease in sleep and, in extreme cases, suicidal thoughts or actions.
SAD is thought to develop from a combination of genetic vulnerability and inadequate light exposure, according to Miklowitz. In Colorado, the peak period for SAD is November through March.
For people suffering from the winter blues and SAD during the long cold months, Miklowitz and other experts suggest increasing one's exposure to light and expanding exercise routines as a first defense.
Some evidence suggests that exposure to light, especially in the morning, alters the level of melatonin available in the brain, according to Miklowitz. Melatonin is a sleep-related hormone that tells the brain it's time to go to sleep, so light exposure may reduce the production of melatonin, he said.
"There is a tendency to stay indoors during winter, so your exposure to light is limited,"
Miklowitz said. "One recourse is to get up early and take a walk in the natural sunlight. But that's a tall order when it's 10 degrees outside and snowing."
People suffering from SAD also can have major difficulties at work, such as a drop in productivity. Miklowitz recommends taking some measures to limit the problems.
"I would suggest checking with your boss about making some changes at work, especially if this is something that happens to you every year," Miklowitz said. "Tell him or her that this is the time of year your mood really drops and you'd like to be able to take four short breaks rather than one long one so you can go outside for a walk in the sun. Or say that you're going to bring in a light box. Most employers will be supportive."
However, if the depressive symptoms don't subside, it's best to see a professional, said Miklowitz. For those who do seek treatment for SAD, antidepressant medications, psychotherapy and light treatment are available.
Light therapy involves being exposed to extra bright light, either from a light box or a special light visor, for a couple of hours each day, according to Miklowitz. For example, light boxes can be set up in the bedroom to mimic an earlier rising sun.
College students also need to be aware of the winter blues and SAD, he said. "The thing to worry about with students is that their grades could fall as the days get shorter, and they may be more susceptible to the effects of alcohol when their mood is low," Miklowitz said. He recommends students try to keep some semblance of a regular sleep and wake cycle and exercise regularly.
SAD has only been recognized as a medical condition since the mid-1980s, so researchers aren't certain what causes it, though most agree that fewer daylight hours triggers a change in mood-altering chemicals in the brain. People who have a history of depression also are more likely to get SAD, he said. Research suggests that about 10 percent of the population is affected by SAD, according to Miklowitz.
Women are four times more likely than men to get SAD, a finding that also is true for depression in general, where women are two to three times more likely than men to be depressed, according to Miklowitz. At least one in six Americans will have an episode of clinical depression at some point in his or her lifetime.