It’s cold. The only time you see the sun is on your commute to work, and the weather keeps you indoors more than you’d like. Winter can be kind of a bummer. But for some, it’s more than that — it’s seasonal affective disorder, otherwise known as SAD.

SAD is more than just feeling a little down or moody during the winter; it’s a form of depression that usually starts in the fall and continues on through the winter months, with symptoms like feeling depressed most of the day, having low energy, oversleeping, experiencing changes in appetite or weight gain, and having difficulty concentrating.

About four to six percent of people have SAD, and up to twenty percent experience a milder form of the disorder. What causes SAD is still unknown, but experts say hormone levels (like serotonin, which drops when exposure to sunlight is reduced), melatonin levels (which affect mood and sleep), and a disrupted circadian rhythm might all have something to do with it.

So what can do you about it, other than not coming out from under your covers until spring? Here’s what experts recommend.

Light therapy
Since a lack of sunlight can contribute to SAD, more light can help. But you don’t have to wake up at dawn and stare at the sun to get it; doctors sometimes recommend light therapy via special lamps (or light boxes) — like this Carex one approved by the Center for Environmental Therapeutics — that are 100 times brighter than regular indoor lighting. Start your morning with 30 minutes near the box (you can check emails or get started on work while you sit there) for the best results.

Check with your doc first, though — there are other types of boxes that may be better for you (like those that simulate sunrise), and morning light therapy is not for everyone (those with bipolar depression benefit more from extra light mid-day). Your insurance may even cover it, but you may need a prescription from your doctor.

Antidepressants
If you’re not a good candidate for light therapy or if it doesn’t work for you, your doctor may suggest antidepressants — usually a selective serotonin reuptake inhibitor that can also be prescribed for non-seasonal depression. There’s also bupropion (you may know it as Wellbutrin), which is FDA-approved for SAD. Remember, these will take a few weeks to fully start working and come with their own side effects, so talk through your options with your doctor.

Cognitive behavioral therapy (CBT)
Consider CBT, either on its own or in tandem with light therapy — that combo was found most effective by researchers in treating SAD. CBT will teach you how to replace the negative thought patterns you’re prone to when you’re depressed with positive and productive ones.

Bottom line? Treat your seasonal depression just as seriously as you would treat non-seasonal depression. While milder forms of SAD can be helped by exercise, spending time outdoors, and eating healthy, if your symptoms are severe enough to affect your basic functioning and quality of life, you owe it yourself to see a doctor and get help, rather than just toughing it out until spring.

Diana Vilibert is a freelance writer and copywriter living in Brooklyn, NY. She loves flea markets, martinis, to-do lists, traveling, and wearing leggings as pants. You can see more of her writing at www.dianavilibert.com and follow her on Twitter at @dianavilibert.