



It's that time of year again. The days are getting shorter, the temperatures are dropping, and stores are already starting to play Christmas music. Unlike many other Grinches I know, it’s not the overabundance of holiday "cheer" that gets to me; rather, it's the end of Daylight Saving Time, which, in practical terms, means that it gets dark out at 4:30 or 5 p.m. instead of 5:30 or 6 p.m. (or 7 or 8 p.m.—ah, the joys of summer).

Some lucky people are impervious to this change. It doesn't seem to make much of a difference to them that it's already dark out by the time they get off work or that the only daylight they see is through a corner of their office window.

I am not one of these lucky people. I am instead one of the many who suffer from Seasonal Affective Disorder (aptly abbreviated as SAD).

There's a lot of confusion about SAD, so I thought I'd go ahead and answer some common questions for you here.

Is SAD real?

Yes. It's not the same as just feeling sad or wishing for summer. If you're tempted to roll your eyes whenever you hear someone talk about it, don't. As with other forms of depression, trivializing SAD sufferers' suffering (try saying that three times fast) can have the effect of making their depression worse, making them feel hopeless or embarrassed to speak up about how they're feeling. Instead, try learning more about SAD so you can have an informed, sympathetic discussion when the topic arises.

What is SAD?

SAD is a mood disorder characterized by depression related to a certain season of the year (typically winter). Onset usually occurs during adulthood and affects mostly women. Approximately 10% to 20% of the population suffers from mild winter SAD, and around 5% suffer from a more severe form of the disorder.

Typical symptoms of SAD include fatigue, irritability, trouble concentrating, and carb cravings. Many people may also experience other symptoms of depression, including lethargy, decreased sexual desire, hopelessness, and lack of interest in normal activities or social interactions. Most importantly, and unlike standard depression, the symptoms of SAD come and go with the change in seasons.

The importance of serotonin and melatonin

A study presented at the 2014 European College of Neuropsychopharmacology meeting found that people with SAD show "significant seasonal differences" in the way they regulate the neurotransmitter serotonin in comparison to the majority of the population. Serotonin is the chemical in humans that regulates our moods—more serotonin means more happiness, and people with depression tend to have low levels of serotonin. This isn’t the first time scientists have noticed a low level of serotonin in SAD sufferers, but, in this new study, the scientists actually tracked the same people from summer to winter. What’s interesting is that the same people who had normal levels of serotonin in the summer had low levels of serotonin in the winter. (cf above: SAD is real!)

A recent Current Biology study found that a small region of the brain called the dorsal raphe nucleus may be responsible for controlling SAD symptoms. The scientists suspected this part of the brain might be involved because prior studies had shown that it is linked to the brain’s biological clock and responds to melatonin, a hormone that controls sleep by regulating the body's day-night cycles. Melatonin is produced at increased levels in the dark, meaning that when the days are shorter and darker, the production of melatonin increases. Add to that the fact that the dorsal raphe nucleus dramatically alters the function of serotonin neurons during different seasonal day lengths, and you can see how SAD occurs.

Do you have SAD?

An estimated 4% to 6% of Americans suffer from SAD, whereas an estimated 16% of people living in Northern European latitudes (e.g., all of Scandinavia) suffer from SAD. It shouldn’t surprise anyone that the incidence of SAD goes up significantly the farther people are from the equator.

Researchers are quick to point out that some people who believe they suffer from SAD are really just feeling regular ol' winter blues. As one scientist says, "We may not have as much fun, we can feel cooped up and we may be less active in the winter. But that's not the same as long-lasting sadness, hopelessness, and problems with appetite and sleep"—real signs of SAD. If you suffer from many or all of the common symptoms listed in this post, you may have SAD (but note that you may suffer from a more traditional form of depression, so you may want to seek professional medical treatment).

So, what do you do if you suffer from SAD?

Light therapy

The most established and talked-about solution is light therapy, which is proven to reduce depression severity for those with SAD provided they remember to do their light therapy daily during the winter months. During light therapy, you sit or work near a special kind of lamp (a "light box," often called a "happy light") that gives off bright light, mimicking natural outdoor light. To be effective, light from the light box must enter your eyes indirectly. Note that this means (1) don’t look directly at it, or it can damage your eyes—just like looking into the sun, and (2) the light needs to be positioned in front of you so it can reach your eyes; it won’t absorb through your skin or while you're sleeping.

The light boxes recommended for light therapy tend to be powerful. They shine a light between 2,500 and 10,000 lux; for comparison, a typical lightbulb tops out closer to 500 lux. This means that you don’t need to have a light box on all day for it to work, and you certainly shouldn’t use it in place of a regular lamp, because there is such a thing as too much of a good thing.

Cognitive behavioral therapy

Alternatively, if you're looking for a longer-term solution or don’t feel like sitting in front of a light box every day, try cognitive behavioral therapy (CBT). CBT is a type of mental-health counseling in which you work with a therapist to become aware of inaccurate or negative thinking so that you can view challenging situations more clearly and respond to them in a more effective way. A 2009 study in Behavior Therapy showed that 7% of CBT participants had a recurrence of SAD the following year, compared to 36.7% of people treated with light therapy. (Or do both: the recurrence rate for the people who tried both CBT and light therapy was only 5.5%.)

Personally, I swear by my happy light and use it faithfully, every day from November to March. Do you have SAD? How do you combat the winter blues?