Access is Everything

Light Therapy for Sad: Brightening Dark Winter Moods

Researchers believe that bulbs can help beat wintertime blues.

Wintertime can have a profound effect on human energy levels, sleep cycles and mood. For many, a deeper depression called seasonal affective disorder (SAD) punctuated by social withdrawal and fatigue closes in. Spending quality time with bright lights might just be the silver lining.

In Sweden, where an estimated one million people have SAD, the season is truly dark. Last December, the average daily sunlight was less than an hour.


“We had a warm autumn with a lot of rain and even more darkness than a normal year,” said Agneta Filén, marketing director at Umeå Energi. Recently, the Swedish energy company launched a project to help bring the light back.

Umeå Energi installed 140 bright fluorescent ceiling lights in several classrooms and the cafeteria at a 2,000-student Dragonskolan high school. Prior to that, in 2012, the company received widespread attention for a project where they installed lights at local bus shelters.

Since Umeå Energi is municipality owned, Filén said the company wanted to give back to the citizens. The classroom lights are also powered by electricity purchased from entirely renewable sources.

This Swedish setup differs from normal light therapy for SAD sufferers, according to Dr. Alfred Lewy, SAD research pioneer and professor emeritus of psychiatry at Oregon Health & Science University.

Light therapy usually entails sitting in front of a fluorescent light box in the morning for a specific duration, according to Lewy. He studied the effects of bright light on biological rhythms in the late 1970s and early 1980s, with researchers that included chemist Sanford Markey and psychiatrist Norman Rosenthal, originator of the SAD acronym.

Through their studies, the researchers found that bright lights could have a therapeutic effect on SAD patients. The spring-like light actually shifted their body clocks.


A common misconception is that light therapy involves grow lights or full-spectrum lights, but the fluorescent bulbs do not contain any ultraviolet light — that would be harmful. Lewy said that, at calibrated distances, the bulbs  can usually deliver 2,000 to 10,000 lux and are among the most inexpensive out there.

Each light box contains several cool fluorescent bulbs protected by a Plexiglas diffuser. “The distance the eyes are from the light fixture is absolutely critical,” Lewy said. “You look at it from an angle, such as from the side, and you scan your eyes across it for a few seconds a few times a minute.” This lasts between 30 and 120 minutes, depending on the therapy.

In Sweden, the fluorescents are in the ceiling. According to Lewy, that distance may prevent people in the classroom from getting sufficiently bright light.

“One would have to go there with a light meter at eye level and see what the intensity is to see if it’s going to be affecting their circadian rhythms,” he said.

Michael Terman is a professor of clinical psychology in psychiatry at Columbia University and an expert in environmental therapeutics. He co-authored the 2013 book “Reset Your Inner Clock: The Drug-Free Way to Your Best-Ever Sleep, Mood, and Energy.” 

Research suggests that looking at bright electronics screens late at night can disrupt sleep cycles. The opposite may be true. In principle, looking at a bright LED screen first thing in the morning should be beneficial, Terman said. However, an LED computer screen alone can’t deliver optimum light for therapy the way a fluorescent light box can.

The setup Terman suggests has room for patients to use a laptop while they’re sitting in front of a fluorescent light box. “In my recommended configuration, the user places his or her laptop under the light box and does not look directly at the light box screen,” he said.

Like Lewy, Terman expressed skepticism about the classroom setup in Sweden and doubted that the installation is optimal for shifting circadian rhythms.

“The schoolroom regimen offers widely variable times of exposure,” he said. “I don’t mean that the Umeå application is necessarily ineffective, although its placebo component is likely very high.”

Although many people feel energized in the presence of bright lights, the exact mechanism isn’t known yet. As a scientist, Lewy said his approach has been to do well-controlled studies with placebo controls and look for biochemical and physiological mechanisms.

However, as a clinician, Lewy said he’s not against placebo effects as long as they don’t hurt you or your wallet. “If you feel better doing this, you should do it.”


Alyssa Danigelis is a professional journalist covering the intersection of technology with sustainability, business, media, arts and design. Her writing has appeared in outlets that include MIT’s Technology Review, Fast Company, Inc. Magazine, Live Science and Discovery News. 

Photos by Andreas Nilsson.


Share This Article

Related Topics


Read This Next

Read Full Story