The symptoms of SAD are feeling sluggish and withdrawn, craving sweet and starchy foods, gaining weight, and sleeping whenever and for as long as you can. Sound familiar? If so, you may also be one of the 10 million Americans with full-blown SAD. And more than twice as many people experience less serious versions of this disorder.
More Sun, Please!
In people prone to SAD, less sunlight triggers greater biochemical changes in the brain than it does in the rest of the population. This results in a disturbance in the natural cycles of the body that control sleeping, wakefulness, and hormone secretion.
Our internal biological clocks are synchronized to the 24-hour light/dark cycle. This allows us to stay alert in daylight and to grow sleepy as the sun begins to set. The invention of the light bulb (and even earlier the discovery of fire) has led us to run our lives counter to our inborn cycles. No longer living a primal life, we are called upon to function during hours of darkness. In fact, can you imagine the slowdown if everyone slept from darkness until daylight in the late fall and winter?
Melatonin is a brain chemical that plays a big role in signaling our body when to sleep. The amount of light determines how much melatonin is released and secreted into the bloodstream. The less light, the more melatonin is released, triggering sleep and lowering body temperature. As the sun rises, melatonin release is slowed, body temperature rises, and we begin to awaken.
As the nights grow longer and more melatonin is present in the blood, the amount of time spent sleeping or feeling sleepy increases, particularly in those vulnerable to SAD. Elevated daytime blood levels of melatonin can characterize those who are vulnerable.
Many people who experience SAD will become melancholy to the point of occasionally experiencing real grief. Others are more anxious or irritable than usual. Symptoms may include fatigue, depression, difficulty concentrating, social withdrawal, increased sensitivity to rejection, reduced activity, increased appetite, and reduced libido.
On a physical level, people suffering from SAD need at least an hour or two of extra sleep. They also feel a marked decrease in energy, with physical activity of almost any sort seeming to be “just too much.” They also tend to overeat (especially carbohydrates) and gain weight.
Help is Available
For SAD patients, I prescribe exposure, from October through April, to a set of full-spectrum fluorescent lights every day. Effective relief is possible with daily exposure of 30 minutes at a light level of 10,000 lux (equal to early morning sunlight) of high-intensity, artificial sunlight.
I also prescribe daily intake of 900 mg of St. John’s wort, which appears to be almost as effective as light therapy—for more convenient relief. My own clinical experience has shown that many people with less severe forms of SAD do quite well on St. John’s wort alone, without the need for the lights. But research shows an even stronger effect when the herbal and light therapies are combined. The B vitamins, particularly B6, are also important for maintaining adequate levels of neurotransmitters.