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Seasonal Affective Disorder (SAD)

Continued from: Seasonal Affective Disorder: Case Study

Treatment of SAD

The secretion of melatonin is an important chemical signal for regulating many different seasonal rhythms in animals. The nerve pathways involved in the suppression of melatonin secretion by light pass through parts of the brain that are important in regulating many of the physical functions that are disturbed in depression, such as eating, sleeping, weight control, and sex drive. (Rosenthal 1989, 10)

Dr. Lewy reasoned that since bright light is necessary for melatonin suppression in humans, it might similarly be necessary for altering mood and behaviour.

If the suppression of melatonin required much brighter light than ordinary indoor fixtures provided, then perhaps bright light might also be necessary in order for the brain to perform other mood-related functions. (Rosenthal 1989, 10)

The idea of treating depression with artificial light is not new. Already in 1924 a British researcher observed: It is obvious what a stimulating and beneficial influence artificial sunlight can exert on those whose fund of energy is seriously depleted by nervous or mental disorder, especially during the dull, sunless and depressing months of our British winter." (Humphris, F.H. Artificial Sunlight and Its Therapeutic Uses. Oxford: Humphrey Milford Oxford University Press, 1924. (221-23)) Since the 1980 discovery that high-intensity artificial light can suppress melatonin secretions, studies using light to treat SAD have been ongoing continuously. (Hyman 1990, 100)

Presently, lamps of approximately 10,000 lux are used, the amount of light to which one would be exposed on a sunny spring morning. This is about twenty times brighter than ordinary room lighting. The light is placed at eye level, and patients are usually instructed to sit about twenty inches away from the light for approximately half an hour each day (Appendix 2). People with SAD report a sense of calmness and alertness under the lights, and frequently an energy surge after approximately 20 minutes. They feel more cheerful and energetic, sleep and eat less, concentrate well, become more sociable, and stop craving carbohydrates. In many cases they feel and behave as they would in spring or summer. The changes do not begin right away, but within two or three days after beginning of the therapy. Once light therapy stops, those with SAD often relapse into depression within a few days. (Hyman 1990, 101)

In the case with Selena, three days of light therapy were enough to begin the improvement, a week - to let her think clearly, and after a month - the seasonal depression was forgotten. The next fall, she was very careful to start the light therapy before the feeling of depression came, and the everything was well up to the day when she a cat turned over the light box breaking the fluorescent tube. In the week before the new one could be delivered, Selena was thrown back into the very familiar feeling of melancholy.

One exciting new research development in the area of information processing by the brain has been done by Dr. Connie Duncan and her colleagues at the NIMH, who have measured the brain wave pattern responses to visual stimuli. A certain part of the brain wave response corresponds to a person's ability to attend to a stimulus. These researchers have shown that this part of the brain wave increases in strength in patients with SAD after they have been successfully treated with light therapy. This change occurs at the same time people begin to feel better and their ability to think improves. It has been very reassuring for the patients to realize that their ability to think can be objectively measured and shown to change after light therapy. It helps them to recognize that they are suffering from a problem in brain function and that their cognitive difficulties are not their fault. (Rosenthal 1989, 59)

The benefit of increasing environmental light can be obtained not only from formal therapy in front of a light box, but whenever one's environment is brighter. Some people have several light boxes in the house, which gives them more exposure without the feeling of being trapped in one location.

Enhancing light levels at home or in the workplace may be helpful, even if this is accomplished by installing more lights on the ceiling or placing more lamps in the room.

Many of the SAD patients find creative ways of carrying this out. Dark wood paneling can be replaced with light-coloured wallpaper, for example.

The main practical value of knowing how seasonal one is relates to how likely one is to benefit from increasing the level of light in his/he living environment. Many research studies have shown that most people with marked winter difficulties - those suffering from SAD - will benefit enhancing their environmental lightning. (Rosenthal 1989, 42)