Saturday, November 24, 2007

Shedding Some Light on Seasonal Affective Disorder (SAD)

First you notice a loss of energy. You're not as chipper in the morning as you usually are. You find yourself snacking more often to try to jack yourself up, but you simply put on weight. You're not as enthusiastic as usual, and sometimes you're even feeling in the dumps. You don't have a history of depression--and you certainly don't have the signs of major depressive disorder--but it certainly feels as though you're down.

Interestingly, as many as two-thirds of all people who display signs of atypical depression evidence seasonality to their symptoms. This seasonal syndrome, known as SAD (seasonal affective disorder), affects roughly 10% of individuals in winter regions with reduced sunlight. My own experience with SAD began in Syracuse, NY, where I taught on the faculty of an academic department of psychiatry and ran a counseling program for medical and health science students. Quite a few of these students experienced symptoms of lowered energy and mood that were seasonally related.

To this day, even though I'm in sunnier suburban Chicago, I keep a phototherapy light in my office. This cranks out the light equivalent to a sunny day. Although I personally do not experience a full-blown SAD, I do experience the subclinical signs commonly known as winter blues. The daily dose of full sunlight has been helpful in starting my days--quite literally--on a bright note.

Studies in Finland find that the combination of exercise and light significantly improves seasonal mood declines. Interestingly, the authors found that even healthy individuals without winter blues benefit from the combination of light and exercise. Their work suggests that the light exposure has an even greater impact on mood than the exercise. My own experience is that light therapy is often sufficient for people who experience those winter blues; those who experience more profound depressive symptoms in winter can also benefit from a course of anti-depressant medication.

Mood affects decisions and can also impact concentration and other aspects of performance. Seasonal patterns of mood decline often go unnoticed. A careful investigation of your own mood patterns may help you take the steps to smooth your equity curve when the dark, dreary days of winter are upon us.


StockMarketTechnician said...

Hi Brett,

I have often considered buying a light box, but keep putting it off. I am back to considering it again.


There are some studies that indicate that just 10 minutes-a-day of sun-light can produce a sufficient amount of "natural" vitamin D to have a significant effect on the development of most cancers. Vitamin D is produced in the epidermal or outer layer of the skin when ultraviolet radiation reacts with 7-dehydrocholesterol.


Exercise has some advantages to health that most people do not think about. It increases blood flow to the various filtering systems throughout the body: lungs, liver, kidneys and lymph nodes.

The lumph nodes are located in the lymphatic system, which is a collection of tubes that transport watery waste from the tissues back to the circulatory system, where the waste can be removed by the liver, kidneys and lungs. The lumph nodes are also a filtering system removing bacteria and viruses from the body, and an important system to start a series of defensive actions against cancer.

However, fluids can only pass through the lymphatic system when muscles expand and contract. This only occurs when we move. The more we move muscles, the better our bodies can keep our tissues clean and healthy.

No muscle movement equals no removal of waste in our tissues, and no defense actions against diseases.



If you suffer from SAD, as I have for many a moon, it's useful to remember that when or if you move.

I moved to Seattle, a town known for its 'Winter Blues', a little over a year ago and high on my list of priorities was an apartment with plenty of light. I even went to far as to take a compass with me to make sure I'd be getting that morning sun.

I pay a hefty premium for the light, the windows and the view; but I'm certain that without it both my mood and consequently, my trading would suffer.

B said...

Is it important to use the light box at a specific time each morning or just sometime in the morning? I found some good advice here too: but I think I need a light box...

Also, how do you find the "right" light box?

Brett Steenbarger, Ph.D. said...

Hi B,

Morning (early) is usually recommended. The Sun Box unit I use was the one used in the NIMH clinical studies of light therapy, so that's why I went with that--