Whether or not you have seasonal affective disorder (SAD), a type of depression with a seasonal pattern, at some point in the fall and winter months, you may have considered purchasing a therapy light. The sky is gloomy, the sun barely makes an appearance, and basking in light sounds gorgeous, even if it is artificial. But as you hover over the "Add To Cart" button, you might be wondering if this light therapy thing actually works to cure your winter blues?
Well, the most promising benefits of light therapy seem to be related to mental health and mood. The American Psychiatric Association (APA) has long recommended light therapy as a treatment for SAD, as well as major depressive disorder, a serious form of depression, says Elizabeth Saenger, PhD, a psychologist who specializes in mood disorders and director of education for the Center for Environmental Therapeutics. In fact, a 2015 study compared the effects of light therapy to antidepressants in patients with major depressive disorder, and found that light therapy alone or with an antidepressant was significantly more effective than just taking medication.
So, why does sitting in front of a light have such an effect on people with depression? It's not as simple as it seems, and it's likely related to our circadian rhythm, or biological clock. When light hits cells in the retina of our eyes, it carries a message to the brain, Dr. Saenger says. Part of the white light in therapy lights activates specific receptors in the retina that "energize us and synchronize circadian rhythms," she says. These cells carry a message to the part of the brain that's known colloquially as the "inner clock." So, the broad theory is that light therapy helps to address these circadian rhythm issues that tend to be common in people with depression.
To be clear, using a light box can't simply "cure" depression, but it's supposed to be one tool involved in treatment. Light therapy — using a light box or getting exposure to the sun — serves a different purpose depending on what it's being used to treat. And light therapy is helpful for a variety of health issues besides depression: recent research suggests that light therapy can be help with bipolar depression, improve sleep quality for people with Parkinson's disease, and improve the quality of life of fibromyalgia patients, she says.
Even if you don't have clinically diagnosable depression, or one of those other conditions, light therapy could be useful. For example, if you're having trouble adjusting to a new sleep-wake times, using a light box temporarily could help you gradually adapt to your schedule. However, in order for light boxes to be useful for treating SAD or depression, you'd have to use them daily for 30 minutes for a couple weeks before you anticipate becoming depressed, in order for it to be sufficient, Dr. Saenger says. Also, you can't just turn on your light whenever you're feeling bummed, because consistent timing is crucial in making light therapy "work," she says. (You can take this questionnaire to determine the best time for you.)
If you're curious about using a light box, talk to your therapist or healthcare provider about whether or not it's right for you given your current treatment plan. Some therapy lights can be expensive, so it's your call. But, "the bottom line is that light, mood, sleep, and circadian rhythms are all interrelated," Dr. Saenger says. "Paying attention to all of them, and their interactions, is vital to good health."