Jefferson scientist's study of SAD took him to space and back

Light, or more precisely the lack of it, is literally one of the most depressing things about winter.

In fact, each year, winter's gloom makes 1 percent to 5 percent of us so miserable we'd qualify for a diagnosis of major depression. Up to a quarter more of us just feel sluggish, sleepy, and unusually attracted to carbs. Normalcy returns with May's flowers.

George Brainard's fascination with this phenomenon, known as Seasonal Affective Disorder, or SAD, has taken him from Earth to space and back again. The Thomas Jefferson University neuroscientist's curiosity about the biological impact of light found connections between SAD Philadelphians, the circadian rhythms of astronauts, and sleep-wake cycles of concussion victims. NASA last month gave him an award for his role in designing new lighting for the International Space Station.

The hope is that better lighting could improve the health of people on the space station, in hospitals, and, eventually, just about everywhere else.

"I predict that lighting will change in every single space in the first world within one to two decades," said Brainard, a small, pleasantly confident man with a fringe of curly gray hair. "I believe there'll be a complete revolution in architectural lighting in a relatively short time."

Brainard predicts that LED lights will displace all the other kinds of lighting in homes and offices. These will offer more flexibility in brightness and color that "can probably be used to improve health and well being."

In the meantime, SAD sufferers will have to settle for bright commercial lights that attempt to compensate for winter's shorter days.

Brainard began studying Seasonal Affective Disorder in the mid-1980s. He said scientists still don't know what causes it, but they do know some people experience cyclical depression between October and April. Symptoms are worst in November through March, peaking in January.

SAD has much in common with regular depression. Patients feel sad, sometimes even suicidal. They lack confidence and energy. They have trouble concentrating and care less about sex.

But there are also some intriguing differences, Brainard said. Most depressed people tend to eat less, but those with SAD crave carbs and gain weight - 10 to 30 pounds - during the winter. Nonseasonal depression is associated with insomnia. People with SAD sleep more, although their sleep may be of poor quality.

Early on, Brainard, along with researchers elsewhere, wondered how light was affecting not just mood, but the body in general, the cellular rhythms that should interact seamlessly.

We all know that the way light is processed in our eyes makes it possible for us to see. But, Brainard said, light is also routed on a different path that stimulates the suprachiasmatic nucleus, a part of the brain that drives circadian rhythms. It regulates secretion of melatonin, a hormone essential to a healthy sleep-wake cycle. It also plays a role in body temperature, heart rate, alertness, and cognitive performance.

This has implications not just for SAD, but for jet lag and shift-work problems.

Much of Brainard's work has focused on the relationship between light and melatonin and on the biological role of different colors in the light spectrum.

Bright light suppresses the production of melatonin, a factor in regulating sleep patterns. Brainard's lab also found vision is maximized near the yellow-green part of the spectrum and blue light seemed to have the greatest impact on circadian light reception.

His work on sleep cycles caught NASA's attention because sleep is a big problem on the space station. The astronauts see a sunrise every 90 minutes. They average only 4.5 to 6 hours of sleep. This is especially problematic in space, where mistakes can be life-threatening. Brainard said sleep aids accounted for 45 percent of all the medicines astronauts took.

In addition, the fluorescent lights on the space station are burning out. No one knows why, Brainard said, but the station will be dark by 2017 unless new lights are installed.

So, along with Harvard University and NASA itself, his group at Jefferson has been studying how best to replace the lights next year. The astronauts need good color vision for their work and also need healthy circadian rhythms.

The scientists are testing light panels made of 294 white LEDs and 254 that are red, green, or blue. Brainard's team can create thousands of patterns of wavelengths and is trying to figure out which are most beneficial.

Their work goes on in two labs, one of which is outfitted with replicas of the sleeping quarters senior astronauts use on the space station. Using study subjects, researchers can test the impact of using relatively pale light with a slightly reddish glow at "night" and a bright, slightly bluish light to foster alertness when it's time to wake.

How all this translates into help for those struggling with the gloom of a wintry Earth has not been Brainard's top concern in recent years. He refers some questions to fellow researcher Brenda Byrne, coordinator of Jefferson's Seasonal Affective Disorder program.

In general, Brainard said, he thinks people with serious depression should see a doctor. Studies support the use of both light therapy and/or antidepressants.

Light therapy itself is an unregulated industry. The Internet abounds with options. Brainard said the advice hadn't changed much in recent years: Buy a lamp that emits 10,000 lux of light and sit near it for 30 to 45 minutes in the morning. If you've been sleeping way too long, try to get up earlier.

Byrne said she rarely saw patients who wanted to be evaluated for SAD now. Most people self-diagnose, buy a lamp, and use it somewhat haphazardly. Sometimes it works. Sometimes the lamp ends up on eBay.

"I have a bias toward blue light, but it hasn't been tested as much as white light has," Byrne said.

Michael Terman, a Columbia University expert on SAD who also is president of the Center for Environmental Therapeutics, is not convinced blue light is superior. He recommends bright, white light from well-tested devices.

Michael Thase, a University of Pennsylvania psychiatrist, cautions against evening light therapy. He likens it to drinking coffee at night. "I wouldn't do it after 4," he said.

Kathryn Roecklein, a University of Pittsburgh psychologist and SAD expert, added a third option: Cognitive behavioral therapy. She thinks SAD results from both biological and environmental factors and is working on a test to figure out which patients will - and won't - respond to light.

About half of patients do well with light therapy, compared to 35 percent to 40 percent for antidepressants and 60 percent for therapy, she said. Therapy helps patients reframe negative thoughts such as: "I never do well in winter" or, "It won't be long till I start feeling worse." Patients also learn to replace warm-weather activities they love with winter hobbies or sports.

Luckily, Thase said, many people with SAD are already feeling a little better as the days are lengthening. A southern vacation also helps. "People reliably report they feel better when they get to a southern climate and get some bright, hot sun on their face," he said.

With support from the National Science Foundation, Brainard's team is turning its attention back to Earth. "We have to admit that it's a very small number of people who go into outer space," he said.

The new goal is to study whether better lighting can improve patient recovery. They're starting with concussion patients, who often have sleep problems. Stroke victims may be next. Improving conditions for the people who work in hospitals is another obvious need, but it is not now on the agenda. Ultimately, though, almost anyone who relies on artificial light may eventually benefit from research into how light and seasons affect our circadian rhythms.

"We feel the door is wide open for Earth-based applications," Brainard said.

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