Seasonal Affective Disorder

When fall turns to winter, many people experience bouts of "the blues" -- feelings of sadness and melancholy. For many people, these feelings pass, often with the holidays. But for others -- those affected by seasonal affective disorder (SAD) -- these feelings drag on throughout the winter and can become debilitating.

SAD is a mild form of depression that occurs at certain seasons of the year, especially in the winter. The illness is characterized by loss of energy and sexual drive, restlessness, and often a craving for carbohydrates.

Typically, people begin experiencing SAD between 20-40 years of age, however, it has been found in some children and some older adults. However, people who have SAD often have had similar patterns of feelings in their earlier life as well. SAD is much more prevalent in women than in men. Symptoms usually begin in the fall, peak in the winter, and resolve in the spring.

Signs and Symptoms of SAD include:

  • Depression
  • Loss of energy
  • Anxiety
  • Irritability
  • Tendency to oversleep
  • Overeating, especially foods high in carbohydrates
  • Weight gain
  • Difficulty concentrating and processing information

What causes SAD? 

Researchers first thought that a lack of sunlight affected the levels of melatonin, a hormone. However, studies on the role of melatonin in SAD are inconclusive. Some researchers believe that a lack of sunlight disrupts circadian rhythms, which regulate your body's internal clock. Others maintain that SAD is due to chemical changes that occur in the brain as a result of reduced light stimulation to the retina of the eye. Lower amounts of light hitting the eyes means lower levels of seratonin and higher levels of melatonin in the brain regions. Lower seratonin levels result in depression, whereas higher levels of melatonin result in fatigue and a desire to sleep. 

How can SAD be treated?

Treatment of SAD often involves utilizing interventions that attempt to reverse the chemical changes that lowed daylight cause in the brain. The most common intervention for mild cases of the disorder involve lifestyle changes which allow more opportunity for light to stimulate the eyes. In more serious cases, light boxes, which attempt to replicate the intensity of natural sunlight, are used to stimulate eyes.

Researchers at more than 15 medical centers and clinics in both the United States and abroad have had much success with light therapy in patients with clear histories of SAD for at least several years. Marked improvement is usually observed within a week, if not sooner. Unfortunately, symptoms usually return in about a week when the lights are withdrawn.

Most people must maintain a consistent daily schedule of light therapy beginning, as needed, in fall or winter and usually continuing until the end of April, by which time outdoor light is sufficient to maintain good mood and high energy. Some people can skip treatments for one to two days, occasionally longer, without ill effects, but most start to slump (regress) quickly when treatment is interrupted. 

In some instances antidepressant medications may also be helpful in treating the disorder.

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