Bright light therapy—the use of special fluorescent bulbs that are many times brighter than standard illumination—brings some of the power of sunlight indoors to treat mood disorders. It’s an attractive nondrug approach with few, if any, side effects that’s been shown to be effective for the treatment of seasonal affective disorder (SAD), the kind of depression that tends to arise in the winter and often resolves come spring or summer. And bright light therapy has also been tried for major depression, the more common form of depression that can strike at any time of the year.

Two recent studies provide new insights into how best to treat both conditions.


While earlier studies have found that bright lights can treat major depression, this larger randomized clinical trial compared the drug approach and the light approach alone and in combination. In the study, 122 patients (ages 19 to 60) with major depression got one of these four treatments for eight weeks—30 minutes a day of bright lights…20 milligrams of fluoxetine (Prozac) daily…a placebo…or bright light therapy plus Prozac. The researchers measured response based on a standard depression scale.


• Everyone’s depression symptoms improved. Those who got just a placebo improved 6.5 points on a 60-point depression scale.

• Those taking Prozac improved 8.8 points—just a little better and not statistically significant.

• Those exposed to just bright light therapy improved 13.4 points. That’s a major difference from the Prozac—and statistically significant.

• The best results? Those who had both Prozac and bright light therapy. They improved 16.9 points on the scale.


Bright light therapy is an established effective treatment for SAD, and a different new study confirms this—but with a twist. The researchers compared giving people with SAD either six weeks of daily light therapy (30 minutes in the morning) or six weeks of twice-weekly sessions of cognitive behavioral therapy (CBT). The CBT was tailored to SAD, helping the participants challenge their negative thoughts about dark winter months and to resist behaviors, such as social isolation, that made their moods worse. Each group was encouraged to continue with their respective therapies after the active phase of the study was over.

Both groups got much better in the first year. But in the second year, more of the light therapy subjects tended to relapse into SAD—46%. By contrast, only 27% of the CBT group relapsed.

Why the difference? One reason may simply be the effort that it takes to use a light box every morning. Indeed, more of the bright light subjects had stopped using the therapy compared with CBT users. Cognitive behavioral therapy, on the other hand, is a set of skills that you learn and which become easier to use over time. In other words, bright light therapy is an effective if time-consuming treatment, while CBT not only treats symptoms but can prevent SAD from coming back.


If you experience either major depression or SAD, these studies show that using this nondrug approach can be a very effective way to improve your depressive symptoms without side effects. It’s worth discussing with your doctor or therapist.

But the latter study also suggests that if you are looking for long-term relief from SAD, don’t neglect cognitive behavioral therapy to not only treat SAD but also help prevent it. To learn more about CBT and find a certified cognitive behavioral therapist in your area, visit the National Association of Cognitive-Behavioral Therapists. These days, CBT is so popular you can even get it on an app on your smartphone.