January 22, 2009

Winter Blues Not Helped By Tanning

A leading expert said today that people with "seasonal affective disorder", or SAD, cannot be cured with tanning. 

The condition, also known as "winter depression" or "winter blues" in its less severe form, is often treated with daily sessions of exposure to bright light. And while some reports have linked tanning to improvements in mood, real light therapy uses a completely differently type of light and works through the eyes, a Reuters report quoted Dr. Michael Terman as saying.

Dr. Terman is director of the Center for Light Treatment and Biological Rhythms at New York-Presbyterian Hospital in Manhattan.

Even if artificial tanning did improve mood, the increased risk of skin cancer would far outweigh its benefits, Terman added.

According to The Skin Cancer Foundation, the latest sunlamps produce up to 12 times as much ultraviolet light as real sunshine, putting tanning bed users at greater risk of developing skin cancers. 

Furthermore, UV light can also harm the eyes. Indeed, previous studies have shown goggles used in tanning salons can still allow substantial amounts of the damaging rays to reach the eyes, Terman added.

While anyone can become clinically depressed during the fall and winter months, an estimated one-in-four of those living in the United States' middle and northern latitudes will experience a drop in mood as the days get shorter.

Humans rely on bright morning light to reset our biological clocks every day. But when our daily demands force us to wake up before sunrise, our biological clocks begin falling out of sync with our environment. 

"That is a formula for depression," Terman said.

Light therapy is thought to reset our biological clocks with a properly timed dose of artificial sunshine, and is believed effective for both SAD and less severe seasonal mood disorders. But UV light from tanning beds and booths use to tan the skin is not part of that treatment, nor is light on the blue end of the spectrum, Terman said.

However, despite the lack of any real evidence for their clinical benefit, some companies have hitched their wagons to studies that suggest extra benefits to blue light, and are making blue-light-only light boxes. 

Terman said this type of light is so harsh that it's difficult for people to directly look at.  And since the U.S. Food and Drug Administration (FDA) doesn't regulate light boxes, there is no guarantee that devices on the market will help, and in fact they may even hurt by failing to adequately filter out UV radiation, Terman said. 

Instead, effective light boxes use soft white lights toward the red end of the spectrum, and should ideally emit 10,000 lux of illumination, he said.

Light boxes should also include a filter or diffuser to protect the eyes and skin from UV light, he added.  Staring at a naked bulb would be ineffective and can harm the eyes because the light exerts its beneficial effects at the periphery of our vision.

"There's a tendency to want to self-treat with light therapy," Terman said.

"Self-treatment with light therapy is clearly contraindicated for anyone with major depression. There are too many ways you can do it wrong, and you'll be even worse for it."

Dr. Terman supervises the non-profit Web site Center for Environmental Therapeutics (www.cet.org).  The site provides information on how to select a light box and a self-test people can take to determine if they might need to visit a doctor for seasonal mood problems.


On the Net: