Most people are as excited about winter's arrival as they are about getting root canal. In only a few months, we go from basking in the warmth of 14 hours of sun during summer holidays, to battling snow and slush in near darkness on the commute to and from work. It's not hard to see why many people feel more sluggish and have less of a 'spark' than they do in the summer.

For those afflicted with Seasonal Affective Disorder (SAD), however, the problems go beyond the occasional melancholy. Sufferers are depressed and lack motivation, often feeling tired throughout the day. The impact can mean excessive time lying in bed or watching TV, neglect of usual activities and avoiding contact with friends.

Why does it happen?

While researchers haven't completely pinned down the reasons for SAD, they believe winter's long nights are a major contributor. That's because we use sunlight to maintain circadian rhythms, the internal clock that regulates mood and feelings. When it's sunny and light outside, the brain releases serotonin, a chemical which wakes the body up and is linked to positive emotions or 'happy' feelings. At night, on the other hand, the brain gets a surge in melatonin, causing a drowsy sensation.

Because the nights are much longer in wintertime, though, the brain usually produces less serotonin than it does in the summer. For those afflicted with SAD the amount of serotonin manufactured becomes drastically lower during the winter, resulting in feelings of depression.

Who gets it?

Since darkness is a major factor in the illness, it's no surprise that SAD is more common in northern regions where nights are longer, and that the number of SAD cases increases the further north you go. Overall, between two and three per cent of the general population suffers from full-blown SAD, while an estimated 15 to 20 per cent of the population experience the 'winter blues' or mood changes associated with SAD. Scientists haven't found any cultural or ethnic group more likely to have the disorder, but women are four times more likely than men to suffer from the illness.

SAD Myths

Myth: "The 'winter blues' are the same as SAD." While the 'winter blues' often share characteristics with SAD, SAD is actually a form of clinical depression. Symptoms are generally far more severe and can include strong feelings of hopelessness and worthlessness, severe insomnia and suicidal thoughts or behaviours. Anyone who suspects themselves or a loved one of having SAD should seek professional help immediately.

Myth: "The disorder hits you suddenly, without warning." SAD tends to creep up slowly, increasing as fall progresses into winter, and the days become shorter. As spring approaches, the symptoms lessen very quickly.

Signs of SAD

Most SAD sufferers have similar symptoms. Starting in October or November and trailing off in March or April (depending on how far north you live), these can include:

• feeling uninterested in doing usually fun things;
• craving foods with starch (like potatoes and bread) and eating considerably more;
• gaining weight;
• suffering from joint or stomach problems often;
• having trouble getting up in the morning and often wanting an afternoon nap;
• feeling tired and slowed down much of the time;
• having lower sexual desire and function;
• having trouble concentrating;
• if you are a woman, worsened premenstrual syndrome symptoms.

Treatment

SAD can be hard to live with, but it's also highly treatable. A few options include:

Light Therapy: Because SAD results from a lack of light, one of the most effective treatments is phototherapy, which exposes your body to very bright artificial light for extended periods of time. This generally means lying in front of a specially designed fluorescent "light box" between 20 minutes and two hours a day, usually right after waking up. The equipment is available for home use, although it's also possible to receive treatment in a clinic.

Cognitive Behaviour Therapy (CBT): This type of therapy works by trying to discover the negative feelings and beliefs that cause depression, and the replacing them with more positive thoughts. CBT can be used in conjunction with light therapy, and according to some research, is the most effective way of treating the disorder.

Antidepressants: In cases of moderate to severe SAD, when other forms of therapy are not effective, doctors will sometimes prescribe antidepressant medication. However, this form of treatment comes with side effects that can range from insomnia to decreased sex drive.

St. John's Wort: This herbal medicine, found in health food stores, is a natural alternative for relieving the symptoms of mild depression. It may cause side effects, including nausea and headaches, as well as negative reactions with other types of SAD therapy. Consult a physician before taking St. John's wort as problems can arise if mixed with other medications.

Winter Mood Boosters:

If you suffer from SAD or the milder symptoms of the 'winter blues," there are also several simple steps you can take every day to brighten up both your body and mind.

Exercise: Regular exercise not only helps lift the negative feelings commonly experienced by SAD sufferers, it also prevents the weight gain associated with the illness. You don't need to run a triathlon to have an effective workout: just taking a twenty minute walk or jog every day can help you feel better.

Let the sun shine in: Because SAD results from a lack of sunshine, getting as much as you can during the winter months can help in reducing the feelings of depression. Make sure your blinds are open during the day and try to remove any obstacles out of sunlight's path.

Regulate your body clock: In the old days it was simple: you were awake when the sun was out, and in bed when it got dark. Today, you're inundated with artificial light at all of times of day, making in difficult for your body clock to do its job. By turning the lights down - or off - at night, you'll help control the circadian rhythms that naturally govern mood.

Watch what you eat: If you've got SAD, chances are you've developed a craving for pasta or pancakes. But one of the best things you can do is stick to high nutrient, balanced meals.

Cut down on alcohol and caffeine: Caffeinated and alcoholic beverages disrupt your body's internal clock, resulting in a worsening of SAD symptoms. Try cutting down, or even cutting out, your daily intake of these drinks.

It can't be sunny all the time. But that shouldn't keep you from enjoying life, or doing the things you love during the winter months. If you think you're suffering from SAD, or even the 'winter blues,' look to a professional for help, support and advice.