It might seem natural that your mood should match the weather as the winter grays continue to grow.

If these feelings persist for a prolonged period of time or return year after year you may be suffering from Seasonal Affective Disorder.

SAD, a form of depression, is thought to be due to the variation in the amount of sunlight that occurs over the seasons. The most common form is winter depression. As winter draws near, daylight hours are shorter and people experience these symptoms. Spring brings relief for these symptoms, as well as a return of normal energy and mood.

About 6 percent of people suffer from severe SAD. Another 10 to 20% may have milder symptoms. SAD is similar to other forms of depression. Females are four times more likely to get it than men.

SAD can manifest as:

Changes in mood Feelings that are sad, depressed, or irritable for at least 2 weeks. These are signs that you may be more critical of yourself and more sensitive to criticism.

Inability to enjoy life. A loss of interest in activities that are usually enjoyable, feeling like tasks cannot be completed as well as they used to can all be signs of SAD. Feelings of guilt or dissatisfaction can also be a sign of SAD.

You may feel low energy. This illness can cause unusual tiredness and unexplained fatigue.

Sleep changes. SAD patients experience a lower level of energy, which can lead to them sleeping more than usual.

Changes in eating habits. SAD can also lead to a desire to eat too much, especially comfort foods and sweets. This can cause weight gain in the winter months.

Concentration difficulties. SAD can be the cause of difficulty concentrating or a decrease in your ability to complete assignments on time.

Socializing is less important. This depression is manifested by spending less time socializing with friends or participating in extracurricular activities.

It is important to talk with your family doctor if you experience these symptoms. SAD sufferers who are suffering from winter problems can get relief with many highly effective treatment options.

You can find more information on Seasonal Affective Disorder at www.seasonalaffective.org www.familydoctor.org.