As fall morphs into winter and the days get shorter and the weather gets colder, some people may start to suffer from seasonal affective disorder — a type of depression that's related to changes in seasons.

SAD, as it's called, begins and ends at about the same times every year with symptoms starting in the fall and continue into the winter months.

Dr. Debra Wentz, president and CEO of The New Jersey Association of Mental Health and Addictive Agencies, says SAD is a mental health issue that zaps your energy and makes you feel moody.

She says as seasons change, people experience a shift in their biological internal clock or circadian rhythm, which causes them to be out of step with their daily schedule. Shorter days and less sunlight are also factors.

Wentz says melatonin, a sleep-related hormone, has also been linked to SAD and depression because it's produced at increased levels in the dark.

An acute form of SAD affects 6 percent of all people in the U-S, including New Jersey during the winter months, says Wentz. She also says ten to twenty percent suffer from a milder form.

Research shows women are more likely to suffer from the disorder and symptoms are normally not seen in people under the age of 20.

So how do you know you suffer from SAD? Some symptoms include depression, fatigue, losing interest in activities you once enjoyed, low energy, problems sleeping, difficulty concentrating, feeling sluggish or agitated.

But Wentz says one major symptom difference from SAD is that "when you have seasonal affective disorder, you often have an insatiable appetite for carbohydrates, which results in weight gain and that makes people depressed, too."

Wentz says there are ways to cope and prevent SAD. Exposure to high intensity artificial light several hours a day works. If symptoms are recurring, Wentz says the light therapy session could begin before symptoms are obvious. Then you can discontinue the therapy in the spring when you're exposed to natural light.

Another coping mechanism is cognitive behavioral therapy. This helps change negative thoughts and behavior and often prevents the relapse of SAD the following winter, she adds.

Wentz also suggest taking a winter vacation, preferably someplace near the equator where the days are longer. Eat a high-protein, low-carb diet and exercise.

SAD can be confused with severe depression or bipolar disorder, so you want to make sure you have the proper diagnosis.

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