Seasonal Affective Disorder
Seasonal Affective Disorder, or SAD, is a common problem of people living in northern
United States. People who are affected by this disorder commonly suffer from depression,
lethargy, inability to concentrate, overeating and weight gain. People from the north
tend to suffer more from this disorder because of the shortened days. It appears, that
due to the deficiency of sunlight some people suffer from these symptoms. The shortened
days have a hormonal effect on the body that causes these symptoms, and the use of
artificial sunlight is the best way to relieve the disorder.
It was not until recently that SAD was discovered. It was discovered by Peter Mueller,
who was reviewing a case of a 29-year-old woman. He had noticed a pattern, the woman's
depression came in the winters and left in the spring. Over the course of years the
woman moved from city to city. Mueller noticed, that the farther north she moved the
early the depression. Mueller had begun to speculate that the lack of sunlight had
contributed to the women's depression. In order to confirm this he exposed the patient
to artificial sunlight. He found that over a period of time the patient had recovered
from the depression. Today light therapy is the most commonly used method in treating
SAD.
The two hormones that are affected by the sunlight, and are thought to be the cause of
SAD, are melatonin and serotonin. Both of these chemicals "are influenced by
photoperiodism, the earth's daily dark-light cycle" (Wurtman 1989). Melatonin is the
chemical that effects mood and energy levels. In the human body melatonin is at its
highest at night and is lowest in the day. There has been a study done to see if
sunlight has a direct effect on suppressing melatonin. It is known that melatonin levels
in urine are five times higher at night than they are in the day. It was not until a
1980 study that it was known that melatonin levels could be directly suppressed with
light. In an experiment, subjects were woken up at two in the morning and exposed to a
half an hour of artificial sunlight. The findings were that melatonin levels were
greatly decreased. The decline in melatonin usually happens in the early morning, but in
a SAD patient this does not occur until about two hours later. In order to suppress the
levels the patient needs to be exposed to sunlight. It is found, that when the patient
is exposed to the light there is a significant decrease in depression and the craving for
carbohydrates. It is not known if SAD is directly caused by melatonin. We are still not
sure what is the direct cause for the depression of SAD. We do know why people who
suffer from SAD crave carbohydrates.
Serotonin is the chemical that regulates a person's appetite for carbohydrate rich
foods. A patient who suffers from SAD, and is given an artificial shot of serotonin
called d-fenfluramine "leads to a decrease in stress-induced eating" (Scientific American
1986). In each person blood stream we have a hormone known as trypton that is a
derivative of serotonin. When it enters the central nervous system and reaches a group
of cells called raphe nucli it is converted into serotonin. The amount of trypton in the
blood is increased when carbohydrates are consumed. This may explain why many people who
suffer from SAD have an increase their intake of carbohydrates. In testing results it
patients who suffer from SAD when given "an 800-calorie, high-carbohydrate meal (six
cookies), they reported feeling vigorous and energized" (Health 1989).
A large consumption of carbohydrates is one of the symptoms of SAD. In a number of
cases, it has been noted that in the fall a person suffering from SAD will increase their
intake of carbohydrates and decrease in the summer. It is also found, that those who
crave carbohydrates tend to consume most of them in the late afternoon or early evening.
A carbohydrate craver is found to eat 1,940 calories at a mealtime. The average for an
adult female is 1,500 to 2,00 calories, an adult male from 2,200 to 2,700 calories. It
is in the early evening that the craver consumes "an additional 800 or more calories
person per day" (Wurtman 1989). The increase of carbohydrates leads to an increase in
the levels of serotonin that relieves the symptoms of SAD.
The evidence all seems to push towards lack of daylight as the reason for SAD. Little
research, although, has been done on the effects of temperature and barometric pressure
on mental health. These factors change during different times of the year. In his
lifetime Abraham Lincoln suffered from two sever bouts with depression. Both of them
came "during the two largest barometric pressure changes recorded at that time" (Davis
1994). There is the possibility that the symptoms of SAD are caused by other seasonable
changes besides daylight.
Evidently, the best treatment for those who suffer from SAD is light therapy. Although,
we still are not for sure what the cause of SAD is we do know that light therapy
suppresses the symptoms. The human body needs to be exposed to the daylight, and our
everyday lives may hinder our exposure. For example, most people work inside in either
an office or some type of building. This significantly reduces our exposure to daylight.
It was found in San Diego that the male spent in a day an average of seventy-five
minutes in the sun, and the female spent an average of twenty. The human body needs more
exposure to the light to regulate the secretion of serotonin and melatonin.
There is still much testing that needs to be done on SAD. We still are not sure of the
cause but we do have a solution. The best way to help suppress SAD is by artificial sun
lamps, but these lamps are expensive. Many of the bulbs that are used cost over
one-hundred dollars. Carbohydrates are an alternate way to suppress the symptoms, but
the side effect is weight gain. It has been proven in studies, that those who crave
carbohydrates also put on significant weight which is lost in the spring. Exposure to
daylight will suppress the symptoms without any side effects. The best method to regulate
the hormonal balance is by regular exposure to daylight.
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