Could You Have Seasonal Affective Disorder And Not Even Know It?

When it’s cold and dark outside, it’s totally understandable to want to hibernate inside your cozy bedroom watching Netflix all day, every day. But if you find yourself feeling particularly low in the winter—and it’s significantly affecting your quality of life—you may be dealing with something more serious than the winter blues.

You could have something called Seasonal Affective Disorder (a.k.a. SAD). “It’s a real disorder,” says Gretchen Kubacky, Psy.D., a psychologist in Los Angeles, “but because it has this cute little acronym it kind of gets played off in a jokey way.” Cute acronym aside, SAD is nothing to take lightly.

What Is SAD?

SAD is a type of  depression that begins and ends at the same time each year. It typically starts in the fall and lasts through the winter, subsiding when there’s a lot of sunshine, says Kubacky.

The signs and symptoms of SAD are pretty similar to clinical depression: According to the National Institute of Mental Health (NIMH), that means frequent feelings of sadness, hopelessness, and/or worthlessness, seriously low energy levels, trouble sleeping, and losing interest in your favorite activities. That might explain why even your favorite weekly kickboxing class doesn’t get you jazzed anymore.

Related: 12 Natural Ways To Kick Your Stress To The Curb

Another sign of SAD that may surprise you is a hefty appetite. If you’ve got any of the above symptoms and also find yourself dreaming of eating bagels or chocolate cake 24/7, consider it a red flag. SAD often comes along with a strong craving for sweets and starchy foods, says Coral Arvon, Ph.D., director of behavioral health and wellness at Pritikin Longevity Center + Spa in Miami. “This is the body’s way of trying to scrounge up some kind of energy to combat how tired and down you’re feeling,” she says. (Carbs cause blood sugar levels to rise, leading to a spike in energy, after all.)

What Causes SAD?

Docs aren’t totally sure on an exact explanation for why some people develop SAD, says Arvon, though quite a few factors seem to be at play.

Biologically, your body’s levels of melatonin, vitamin D, and serotonin could be to blame. Your brain secretes the hormone melatonin when it’s dark outside in order to help your body wind down for sleep. (When you’re exposed to sunlight, your melatonin production decreases and you feel more awake and energized.) So, if it’s dark more often than not, your body may produce too much of the stuff, making you feel way more lethargic than you do during the summer, explains Arvon.

Similarly, the less time you spend basking in the sun, the less vitamin D your body produces. Vitamin D is crucial for healthy bones and immune function, and research has identified a link between low levels of vitamin D and symptoms of depression.

The final potential culprit is serotonin, a neurotransmitter that helps regulate your mood. In the winter, people tend to produce less serotonin, says Arvon, which could explain why shorter days and frigid temps leave you feeling down in the dumps.

Who’s Most at Risk?

Geography is obviously a big factor. Those who live in not-so-sunny climates far away from the equator (we’re looking at you, Boston and Toronto) are more likely to experience SAD than those who reside in places like Florida, according to a study published in Depression Research and Treatment. In fact, according to the study, about nine percent of people in Alaska have SAD, compared to just one percent of people in the Sunshine State.

And not-so-good news for the ladies: The same study found that women are a whopping four times more likely to have SAD than men, possibly because women generally experience more hormonal fluctuations than men.

Arvon cautions that those diagnosed with bipolar disorder may also be at an increased risk for SAD, since the change in weather may exacerbate symptoms.

Additionally, according to the NIMH, a family history of depression may also up your risk for SAD.

How Is SAD Treated?

The good news is there are lots of ways to help get this condition under control, even when the sun is nowhere to be found.

One of the best things you can do is invest in a light box, says Kubacky. Light boxes emit bright light, which can help lower your melatonin and boost your vitamin D. “They’re low-risk and easy,” she says.

Another game-changer: exercise. Regular physical activity may help to improve feelings of depression and anxiety, according to Harvard Health Publications. Cognitive behavioral therapy (a type of therapy that focuses on developing alternative ways of thinking and behaving) and meditation can help, too, Avron says.

It’s also important to make social connections so that you don’t feel so isolated, and to try to get some fresh air, even on cloudy days, she says. In fact, a study published in Ecopsychology found that regular group nature walks helped to decrease depression and promote well-being in participants.

Related: New Study Suggests A Healthy Diet May Help Treat Depression