- Light therapy is used to treat seasonal emotional disorder (SAD) as it can help control dopamine and serotonin levels.
- For light therapy to be effective, experts recommend that you spend 20-30 minutes daily in front of 10,000 lux light box from the end of September to the end of winter.
- The medical review of this article is a PhD, PDD, MD, MD, of the Pacific Brain Health Center of the Pacific Neuroscience Institute at Providence St. John Health Center in Santa Monica, California. Was performed by Merrill.
- Visit the Inner Health Reference Library for more advice.
Light therapy is considered a first-line treatment for seasonal emotional disorder (SAD), a type of depression that occurs during the fall and winter. Here’s more about this treatment and how to use it effectively.
What is Seasonal Emotional Disorder (SAD)?
About 4% -6% of American adults have SAD, which occurs in autumn and winter, and usually lives in spring and summer. Research has linked SAD to changes in the amount of daylight and found that it is more common in areas that are farther away from the equator and therefore have shorter, darker days in winter.
Gonzalo Laje, MD and MD of Washington Behavioral Medicine Associates, LLC and George Clinton, a Clinical Associate Professor of Psychiatry and Behavioral Sciences at Washington University in Washington DC, says,
“It’s a real thing, and we have a very interesting approach to treatment, not just traditional antidepressants, but also light therapy,” he says.
To understand how light therapy works, it is important to understand the biological causes of SAD. Research shows that people with SAD have three possible biological causes that contribute to their depression during the darker months:
- They have difficulty controlling serotonin transporter proteins. This protein binds to the neurotransmitter serotonin and inactivates it. One study found that people with SAD have more serotonin transporters during the winter months. This results in less serotonin being available, and lower levels of serotonin are associated with depression.
- They produce more melatonin. Melatonin is a hormone that promotes sleep. The body produces it when it is dark, but SAD people produce more melatonin, causing them to fall asleep, lethargy and disrupt their circadian rhythms or disrupted body clocks.
- They produce less vitamin D. Vitamin D, which is activated by sun exposure, can help control mood. Low levels of vitamin D are associated with depression.
How light therapy works
Light therapy can help control melatonin and serotonin levels, thereby compensating for some of the depressive symptoms associated with SAD.
How light therapy works is that it aims to create a brighter light that people don’t get during the winter months, especially in cold and dark environments.
“There’s a clear relationship between environmental light – sunlight – and mood,” Laaj says. “What light therapy is trying to do is alleviate some of the lack of light with artificial light.”
A 2006 double-blind randomized controlled clinical study found that light improved the symptoms of light therapy in 67% of patients, the same amount as those who saw an improvement in the antidepressant fluoxetine, part of the SSRI class of drugs. Selective serotonin reuptake inhibitors (SSRIs) are commonly prescribed antidepressants.
Experts believe that light therapy is so successful that it regulates the production of serotonin and melatonin. For example, researchers have found that light therapy can reduce serotonin transporter binding, releasing the phyllo-good serotonin hormone available in the brain.
Scientists have also found that increasing daylight with artificial light can lower daytime melatonin levels in people experiencing SAD.
How to effectively study light therapy
Laj says that just living in a brightly lit room is not an effective light therapy. To reap the benefits of light therapy, you need to be exposed to 10,000-lux light boxes for 20-30 straight minutes every day, according to the Mayo Clinic.
For light therapy to work, Laj says you need to sit 1.5 to 2 feet from the light box. It will feel a little uncomfortable because it is so bright.
“It takes a bit of upset to be effective,” he says. “It’s very bright. If you’re too far away you’ll lose effectiveness very quickly.”
Brightness can damage your eyes, so, you should never look directly at the lamp. You recommend reading a book or a newspaper and staying busy while sitting near the light.
Light therapy affects your biological clock, so Laj recommends doing it in the morning, and never in the afternoon, as it can disrupt your normal state of sleep and make it more difficult for you to fall asleep at night.
He recommends that patients do 20-30 minutes of light therapy daily, continuing in late September or early October and during the winter months.
Health matters for light therapy
“While light therapy may seem almost trivial, it can cause problems.” For example, people with bipolar disorder can become manic and they should only use light therapy under the instruction of their doctor, he says. That is why it is always important to talk to your doctor and seek their guidance before starting a mild therapy.
Light therapy, alone, may work for some people, but sometimes others may also need an anti-depressant or counselor, Laje says. If your depression symptoms do not improve or worsen under your treatment plan, see your doctor right away.
Laj says lamps used in light therapy do not emit UV rays, there is no risk of cancer.
Takeoways
Light therapy is an effective way to help control the symptoms of seasonal emotional disorders. Low winter light can affect serotonin and melatonin levels, making you lethargic, tired or depressed.
Spending 20-30 minutes in front of a very bright lamp of about 10,000 lux units is all about eliminating the symptoms of SAD, controlling your circadian clock and making you feel better during the winter months, says Laaj.
“I’m always fascinated by these approaches, it’s simple, effective and generally safe,” he says. “With light, we can help our mood.”
