In the future, for some women who suffer from bulimia nervosa, an eating disorder marked by bingeing and purging, a bright white light may lead them back to health, according to a UND researcher.  

Dr. Kyle De Young, assistant professor of psychology, is studying the effects of “bright light therapy” on women who binge-eat and then purge either by self-induced vomiting or misuse of laxatives and diuretics.

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“There’s evidence that light therapy might decrease binge-eating and purging,” De Young said. “What we’re trying to do is test the mechanism (of light therapy).

“It’s having an effect. We want to know why.”

His research study aims to expand on research which shows that light therapy helps regulate mood by acting on certain chemicals in the brain, he said. He is analyzing the correlation between “negative mood states” and the occurrence of binge-eating and purging.

The light therapy treatment he’s studying is similar to that which is being used to treat seasonal affective disorder, or SAD.

In some people, the therapy alleviates symptoms of depression or anxiety caused by a lack of exposure to sunlight, especially during winter months in northern regions.

Between one and two percent of the population is affected by bulimia nervosa, De Young said. “Between 2.5 and 5 percent of people - at some point in their life - will have bulimia nervosa.” 

About five to 10 percent of college-age women, the most at-risk group, have it, he said.    

Emotional basis

Some researchers suggest that eating disorders are less about food as they are a sign of unhealthy copying with emotional problems. 

De Young said that the causes for eating disorders are “multi-faceted” and may be traced to genetic, biological, familial or socio-cultural factors such as “the pressure to look at certain way.”

“For some people, mood and emotions are important (to understanding the illness) but for others, mood and emotions do not figure in as prominently.”      

In his study, some participants had been diagnosed with an eating disorder and may be in therapy with a mental health professional, but all of them recognized they have a problem, said Nicole Johnson who coordinates De Young’s Eating Behaviors Laboratory.

“They know something is wrong,” De Young said.

At the beginning of the study, participants completed in-depth questionnaires designed to measure their mood and eating disorder symptoms, he said.

This information provided a “base line” of data to compare with data obtained after light therapy was completed, he said.

For six weeks, about a dozen women tracked their emotions and eating behaviors by answering questions on a special web site managed by De Young.

“We asked them how they felt during the day,” he said. “Were they anxious, stressed, happy, excited?

“They also recorded what eating behaviors they engaged in, such as vomiting or misuse of laxatives, and whether or not they fasted or skipped a meal.”

After two weeks, participants were given a light box - a “full spectrum light therapy fixture” - to take home. They were instructed to sit about 16 inches from it for a half-hour between 7 and 8 a.m. daily for two weeks.

The box is fitted with a 10,000-lux bulb which gives “the therapeutic equivalent of being outside on a bright day,” he said.

The women were cautioned to not look straight at the light, but they could do other things - read, work on a computer, eat breakfast or apply makeup.    

In the final two weeks, without light therapy, the women continued to answer questions and were re-interviewed.    

Many effects

Light affects a person in many ways, including a direct effect on appetite and the tendency to act impulsively, De Young said.

It also affects the body’s ability to regulate circadian rhythms - the body’s internal “clock” that tells us when to sleep or be awake. Those rhythms are influenced by external cues, primarily daylight.   

“Light appears to be the strongest signal for the timing of our rhythms, for setting that clock,” he said.

“There’s some evidence that people with bulimia nervosa have disregulated, or out-of-sync, circadian rhythms. They may have a delayed phase for hunger and appetite but have a regular phase for sleeping. They may wake up at 2 a.m. starving,” he said.

“Light (therapy) has been known to synchronize those rhythms.”    

Johnson said, “They may get up in the middle of the night and eat a whole jar of peanut butter or make a batch of macaroni and cheese and not remember it the next day.”

“If light therapy works in people with bulimia nervosa… it may be by getting those rhythms in sync,” De Young said.   


The use of light therapy to treat eating disorders is “under-researched” and considered to be experimental, he said.

In the eating disorders field, light therapy could become a welcome alternative, especially for treatment of bulimia, he said.

The first course of treatment for people with eating disorders is cognitive behavioral therapy and medications, he said. “But if (that) hasn’t worked well, light therapy might make sense.”

About 40 percent of individuals with bulimia nervosa or binge-eating disorder who are treated with existing treatment methods “do not substantially benefit, indicating that treatments need to be improved,” he said.

“Some people may be more sensitive to light exposure than others, so light therapy may be useful for a subset of the eating disorders population.” 

Light therapy, which has few or no side effects, is also inexpensive when compared to the cost of taking anti-depressant medications for years, he said.

In 2012, De Young received a New Faculty Research Award from UND to launch his investigation and build a foundation for a grant proposal that would attract federal funding.

He plans to apply for funding this fall from the National Institute of Mental Health to continue his research on this therapy.