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Adverse Effects of Lack of Daylight

Lack of daylight — the adverse effects are real

For most people, the change of seasons does not affect them in any way in particular. But for some, seasonal changes may promote feelings of depression. These people may suffer from Seasonal Affective Disorder (SAD). According to the National Institute of Mental Health, a milder form of SAD called sub-syndromal SAD (S/SAD), (also known as the Winter Blues), and SAD are characterized by periods of depression during the fall and winter months which subside in the spring.

During the winter, people affected by SAD, may experience feelings of depression, fatigue and sadness. They may gain weight because their appetite increases, especially for carbohydrates. They may have trouble concentrating and completing tasks. They may withdraw from friends and family. They may tend to sleep for longer periods of time and become irritable. Children who are affected by SAD may exhibit such symptoms as irritability, difficulty getting out of bed and problems at school during the fall and winter. An individual SAD sufferer does not need to show all of these symptoms.

It is estimated that about 10 million Americans suffer from SAD, while 25 million suffer from S/SAD. About 80% of SAD sufferers are women whose symptoms typically appear during their 20's. Premenstrual mood changes are often worse for these women during the winter.

Many scientists believe that SAD is caused by light deprivation. Research has shown that humans react physically and emotionally to changes in the amount of daylight. Daylight helps us adapt to the changing seasons and the lengthening or shortening of days by altering our biological clocks. But exactly how lack of light affects us is still unknown. What we do know is that bright light seems to affect the production of the hormone melatonin, which in turn may affect our sleeping patterns. Light deprivation may also disrupt the production of hormones that control how we react to stress.

For SAD sufferers, the primary treatment is exposure to artificial bright light, which relieves symptoms in 75% of patients. Most patients report improvements within 2 to 14 days of starting this therapy. During therapy, the patient sits near a light box which shines light more than 50 times brighter than indoor light. The amount of light and the duration of the treatment varies from patient to patient. Since it is not recommended that a person stares at the light, patients can spend their therapy time doing other activities such as reading or writing.

In the past few years, there's been a great deal of research into new techniques for the treatment of SAD, according to Michael Terman, Ph.D., Director of the Winter Depression program at Columbia-Presbyterian Medical Center and New York State Psychiatric Institute. One of the foremost experts in the field of SAD research, Dr. Terman says that three of the most promising developments are:

• 10,000 lux tilted light box. Ten years ago, light therapy required exposure sessions of 2-4 hours a day. The new method requires just 30 minutes, and usually takes place just after waking or at breakfast. This method has shown no significant changes in, or hazard to the eye, due to strict ultraviolet emission controls. However, bright light therapy may cause headaches for those who are prone to headache. This can be avoided with one of the following alternate treatment methods:

  • Dawn simulation. Dr. Terman indicated that in his early biological research, it was discovered that the dim light of natural dawns affects the internal biological clock to keep it in sync with day and night. In some people with SAD, that sync is lost in winter because of the later sunrise. Dr. Terman created a bedside device that mimics a spring or summer dawn in winter. A light diffusion mechanism above the bed bathes the sleeping area in the dawn light and is timed according to when the user wants to wake up. During the final hours of sleep, the light slowly builds up a glow starting from darkness and ending with sunrise. Once awake, treatment is complete for the day. So far, according to David Avery, Ph.D., an Associate Professor of Psychiatry at the University of Washington School of Medicine, "We don't know if dawn simulation is as good as the bright light therapy. There have been fewer dawn simulation studies. These studies indicate that dawn simulation is effective, but the sample sizes of the studies are small." Both types of treatments are not mutually exclusive and may be used together.

  • Negative air ionization. This treatment, also originated in Dr. Terman's clinic and doesn't involve light at all. According to Dr. Terman, "A high concentration of negative ions, produced by an electronic device, creates an ion balance in the air circulation that is typical of summer—especially at the beach and by waterfalls—but is often deficient indoors in winter—especially in dry, heated homes". The ions are imperceptible, although you may notice that the air is fresher. Studies have shown that after about 3 weeks of treatment for 30 minutes a day patients using negative air ions showed improvement similar to that of patients using light therapy

Can those who suffer from S/SAD also benefit from light therapy? Dr. Terman believes light therapy can help these sufferers, "and since the method is so simple and noninvasive, and results are rapid, it makes good sense to try the treatment."

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