Turning back the clock may bring on Seasonal Affective Disorder
With this weekend's shift back an hour and the shortening of daylight with the coming of winter, some people find themselves sinking into depression. This may be the winter blahs or it could be Seasonal Affective Disorder (SAD). It is estimated that 10 million Americans suffer from SAD and an additional 25 million are hobbled by the winter blues - which can last from October to April.
The farther north of the equator one gets, the higher the incidence of SAD, says Kent Yrchik-Shoemaker, Psychological Services' assistant director for outreach programs. "I grew up in Maine, so anyone who could do it drove as far south as possible when school breaks came. A lot of being outdoors in the daytime, even in winter, helps the light exposure," he says.
The symptoms for SAD are much like those of depression, and can include lethargy, altered appetite, sleepiness, feelings of despair, and poor attention span. It can adversely affect one's relationships at home and at work. Women seem especially prone: 75 to 80 percent of SAD sufferers are women, according to Paul Shield, M.D., an expert in the field whose taped lecture is available through the Self-Help Center in Psychological Services in Rhode Island Hall.
SAD is caused by light deprivation, thus the treatment involves light therapy. The good news is that the effects of treatment can usually be seen in a few days of bright-light sessions. Each session can last from 30 minutes to two hours.
Treatment is based on the interaction of light with the eyes, not with the skin, says Shield. A light box of 2500 watts seems to be effective for most people, he says. A light box costs from $300 to $500 - some insurers reimburse clients for light therapy boxes. A portable alternative is a visor worn directly above the eyes. Light therapy is not recommended for people who have photosensitive skin or are taking drugs that increase light sensitivity, or for those who have had eye surgery. Any light therapy should be done only under the guidance of a health professional.
"The light needs to be intense to be effective, but the full spectrum is not necessary," says Shield. "Ordinary fluorescent light bulbs or halogen lamps are satisfactory. One shouldn't use heat lamps or UV light; they're unhealthy." Looking at the light is the key - a quick glance every few minutes during the session is necessary for the treatment to work.
Those who respond to light therapy may notice that their moods improved as soon as two to four days into the course of treatment. "If there's little or no response after a week, it's most likely not SAD," he says. For some people a combination of drug treatment and light therapy may be effective.
SAD not only occurs with the onset of winter, but can affect some people in the hot months of summer, according to Shield. "It's called Summer Seasonal Affective Disorder. Heat makes some people instantly depressed. They respond better to cold. For them, cold showers, air-conditioning and even anti-depressants seem to work."
The science behind SAD involves the regulation of the neurotransmitter serotonin and the hormone melatonin. The latter is secreted at night by the pineal gland, a pea-sized structure at the base of the brain. Melatonin appears to play a major role in regulating the body's circadian rhythms, says Shield. Melatonin also appears to decrease serotonin levels. "It probably takes two weeks of insufficient light to significantly decrease serotonin, which leads to depression," he says. Popular anti-depressant medications that target serotonin seem to work because they increase serotonin concentration at synapses in the central nervous system.
Basically, bright morning light "resets" the body's clock. Interestingly, in blind people, their circadian rhythms "free wheel," according to Shield, and become asynchronous to a 24-hour day. "If left to free wheel, people's natural biological clocks correlate inversely to their age," he adds. Young people have a biological day of about 25 to 26 hours; middle-agers are about 24 hours; and the elderly tend to run less than 24 hours.
Sources on S.A.D.