7 things you should know about seasonal depression and light therapy

Seasonal affective disorder can be debilitating, but is treatable with bright light

January 2, 2016
Seasonal affective disorder is a form of depression that occurs during the winter months. Experts estimate that 6 percent of the population is affected every year. [Image credit: Flickr user Evil Erin ]

Winter is the time of year for warm cable knit sweaters, Ugg boots and Starbucks’ peppermint mocha. But it also means shorter days and longer nights, spells of cold and darkness. It’s no wonder that many of us feel a little woeful at this time of year — it’s harder to get out of bed in the morning, we’re more tired and irritable during the day, and we just don’t feel like doing very much.

It’s normal to feel a bit blue as winter sets in, but if it’s affecting your work and relationships, it could be the sign of a more serious condition called seasonal affective disorder, or SAD.

“SAD is much more serious than the winter blues,” says psychiatrist George C. Brainard from Thomas Jefferson University. “It’s a type of depression that can be debilitating and requires clinical intervention.”

SAD affects approximately six percent of people in the United States every year, but the good news is that it’s treatable. Here’s what you need to know about SAD and light therapy, the most common method of treatment.

1. SAD isn’t like normal depression

While SAD is a form of depression and shares similarities such as mood swings and feelings of hopelessness, there are three key differences. SAD tends to occur on a seasonal basis, often beginning in autumn or winter and subsiding in the spring. People tend to crave carbohydrates and gain weight as a result. And while depression can lead to insomnia, SAD tends to do the reverse: “So instead of needing 7 to 8 hours of sleep, you might need 10 to 14 hours,” says Brainard.

2. SAD affects both sexes

While it’s true that women tend to be more prone to SAD — nearly three-quarters of those affected are women — men can get it too. In fact, men are often the ones with more severe symptoms. You’re also more likely to be affected by SAD if you’re younger — symptoms normally begin between the ages of 18 and 30.

3. Light therapy can help SAD

The exact cause of SAD isn’t fully understood but scientists believe it’s linked to the lower levels of sunlight we get during the winter months. Light therapy is one of the main ways of treating SAD, where a special lamp called a light box mimics sunlight.

Light therapy has been around since the 1980s and several studies have shown that it’s effective in treating SAD. “As a treatment for a psychiatric problem, light therapy has a remarkably high success rate of 60–80%,” says Brainard.

This may be because light therapy addresses the potential root cause of SAD – lower levels of sunlight, says psychologist Elizabeth Saenger at the Center for Environmental Therapeutics in New York.

“Most other psychiatric interventions, particularly medication, intervene at other points in our bodies, treating the side effects of the decrease in light rather than the original cause.”

4. How you use your light box matters

Using your light box in the correct way can make all the difference in how effective your therapy will be. You don’t need a prescription, but your psychiatrist will be able to advise you on how and when to use your box. In general, you’ll need to sit in front of your light box for 30 to 45 minutes every day. This works best if you do it first thing in the morning within two hours of waking up, says Brainard.

Research has shown that light therapy is linked to circadian rhythms, the body’s internal clock, which can vary from person to person. “Light therapy grew out of the science of circadian rhythms,” explains Saegner, who says that treating SAD with light is backed by credible scientific research.

5. Not all light boxes are made equal

Light therapy isn’t regulated by the FDA, so the quality of light boxes can vary depending on the manufacturer. “You need to know what you’re doing,” says Saegner, “or you could literally get burnt by UV rays or get insufficient lux [illumination].”

When choosing a light box, make sure you pick one that is specially designed to treat SAD — some are used to treat skin disorders. Boxes come in different sizes and designs but they should all emit a bright white light, rather than UV or blue light. You’ll also want to consider factors like its brightness and how you’ll be using it, how much space you have for one in your house, and how much time you have in the mornings.

You can buy a light box online for between $60 and $300 — your insurance company may be able to reimburse you for this cost. If you’re hesitant about making a purchase, you can rent one out first to try.

6. Light therapy has side effects too

It’s a misconception to think that light boxes emit light of such high intensity that they’re dangerous. Most boxes emit light of a 10,000 lux intensity, which is similar to the type of light you would get at dawn, says Brainard. In comparison, typical indoor lighting averages between 50 to 250 lux.

Light therapy is generally considered safe but as with all treatments, there can be side effects if used incorrectly. These include eye strain, dry eyes and possibly hypomania, which is the reverse of depression where “a person can feel racy or tuned up,” says Brainard. Part of using a light box correctly involves sitting at the right distance from it, as specified by the manufacturer, and not staring directly into the light.

7. Light therapy isn’t dawn stimulation

You can also buy a special type of alarm clock that wakes you up using light. The idea is to stimulate a sunrise, where light gradually gets brighter over, say, 30 minutes before your desired alarm time. This dawn stimulation is different from the bright light therapy we’ve been talking about so far. It hasn’t been studied in as much detail as light therapy but there is evidence to suggest it might be useful in treating SAD too.

If you suspect you might have SAD, speak to your doctor. He or she will be able to run a few tests to diagnose you correctly. Your doctor will also discuss what treatment options are available and what would work best for you. Light therapy is often one of the first treatments recommended because it’s simple, unobtrusive and largely effective. But there are other ways to treat SAD too — with antidepressants, melatonin treatment, counseling or general changes to your lifestyle.

Winter can be a tough time, but remember help is always on hand to fight those blues away.

About the Author

Sandy Ong

Sandy hails from sunny Singapore where she earned a B.S. in life sciences. She then moved to London for a M.S. in forensic science before deciding testing crime scene samples wasn’t as cool as it sounded. After spending some years as a medical writer, she moved across the pond to further her love for science writing.


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