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There’s something about short, dark days and unforgiving winter weather that can make life start to feel like one long, gloomy blur. If you find yourself with a constant desire to cancel plans and stay in bed around this time of year, you’re not alone. Around 1 in 20 adults in the U.S. experience a form of winter depression known as seasonal affective disorder (SAD). Even more people experience a milder seasonal depression called the “winter blues.”

According to the American Psychiatric Association, January and February are often the most difficult months for people in the United States with SAD. Anyone can experience seasonal depression, but it’s more common among women, people who live farther from the equator, and those with a personal or family history of depression.

Here, we break down what SAD looks like, what causes this mental change during the winter months, and what steps you can take to beat seasonal depression.

Digital art showing a woman's happy face with a sad face in the background

What is seasonal affective disorder (SAD)?

Seasonal affective disorder is a type of depression also called SAD, winter depression, or seasonal depression. SAD symptoms are linked to the change in seasons, so they usually appear around the same time every year. For most people, SAD causes depression symptoms during the winter. Some people may experience SAD during the spring or summer, but it’s less common. Like other types of depression, SAD is very treatable with at-home and medical remedies.

Seasonal affective disorder vs. seasonal depression

Seasonal affective disorder and seasonal depression are two names for the same condition: depression that happens only during a specific season (usually the winter). For depression symptoms to be diagnosed as SAD or seasonal depression, they should meet these criteria:

  • Symptoms get worse during a specific part of the year.
  • Seasonal depressive episodes are significantly worse than any depressive episodes during the rest of the year.
  • Symptoms have appeared and resolved around the same time each year for at least two years.

Is seasonal depression real?

Yes, seasonal depression is a real mental health condition that many people deal with every year. So, if you’re feeling extra low energy this winter, it’s worth bringing up to your healthcare provider. It’s easy to try to brush off fatigue, sleeplessness, and mood swings as a result of the hectic holiday season, but they may be signs of a real problem that needs to be addressed. Your provider can help you figure out whether SAD is causing your winter blues and help you care for your mental health, no matter your diagnosis.

What causes seasonal depression?

Researchers still don’t know the exact cause of seasonal depression, but a few known factors may contribute to SAD symptoms. First, the decrease in sunlight during the winter may disrupt your body’s circadian rhythms (internal clock). Your circadian rhythms control some of your body’s processes, like sleep through cortisol and melatonin secretion at just the right times. When these rhythms are disrupted, your mental health may pay the price.

Graph showing temperature, melatonin, and cortisol fluctuations throughout the Circadian rhythm

The lack of sunlight during winter may also trigger a drop in serotonin, a hormone and neurotransmitter that helps regulate your mood. Low serotonin levels have been associated with sleep problems, anxiety, depression, and other mood disorders. Melatonin, a hormone that helps synchronize circadian rhythms across your body, may also play a role in SAD. If short winter days affect your body’s melatonin production, you may experience irregular sleep patterns that wreak havoc on your energy and mood.

You may have a higher risk of seasonal depression if you:

  • Have a personal or family history of depression or bipolar disorder;
  • Live far north or south of the equator;
  • Have low vitamin D levels;
  • Are female;
  • Are between ages 18 and 30.

Can seasonal depression happen in the summer?

Seasonal depression can happen anytime. Most people with SAD experience symptoms during the fall or winter months, but it’s possible to experience seasonal depression during the spring and summer too. (Though, by definition, it’s not possible to have SAD that affects you during the winter and summer.)

Summer seasonal affective disorder is uncommon, and it’s less understood than winter seasonal depression. Warm-weather depression may be triggered by increased heat, humidity, or pollen during the summer months, but more research is needed to determine exactly what causes summer SAD.

Digital art showing an overwhelmed woman experiencing joy, exhaustion, sadness, and anger

What are the symptoms of seasonal affective disorder?

Many people feel a general moodiness or urge to hibernate around the end of the year. It’s a natural response to being stuck inside during a cold, dreary winter. SAD symptoms go beyond that. Seasonal depression symptoms can be overwhelming, and they may make it difficult or impossible to keep up with your plans and responsibilities. Common signs of SAD include:

  • Persistent sadness or feelings of depression;
  • Loss of pleasure or interest in the hobbies you used to enjoy;
  • Changes in your sleep pattern;
  • Changes in your appetite;
  • Fatigue or low energy, even with increased sleep;
  • Increased fidgeting or trouble sitting still;
  • Slowed movements or speech;
  • Increased feelings of guilt, worthlessness, loneliness, or hopelessness;
  • Difficulty concentrating or making decisions;
  • Thoughts of self-harm, death, or suicide.

Fall and winter SAD symptoms often include oversleeping, carbohydrate cravings, weight gain, and increased tiredness. Spring and summer seasonal depression symptoms are a bit different. With summer SAD, you’re more likely to experience insomnia, decreased appetite, weight loss, and increased irritability, agitation, and anxiety.

How long does seasonal depression last?

Seasonal depression typically lasts a little bit longer than its name suggests. Most people with SAD start experiencing symptoms in late fall or early winter that last until spring or early summer. With summer SAD, symptoms appear around March and start to go away in October. The American Psychiatric Association estimates that SAD lasts around 40% of the year—a little under five months.

Digital art showing a depressed woman under a raincloud with a sunny sky in the distance

How to combat seasonal depression

If you’re experiencing symptoms of summer or winter SAD, your healthcare provider can help you choose a treatment plan that’s right for you. This may include some combination of talk therapy, medication, light therapy, and lifestyle changes.

Talk therapy

Talk therapy, also called psychotherapy, may help you find healthy ways to cope with your SAD symptoms. Cognitive behavioral therapy (CBT) is a form of talk therapy that’s shown to produce long-lasting improvements for people with seasonal depression. During CBT, you learn how to spot and change harmful behaviors and thought processes, manage stress, and implement lifestyle changes that can improve your mental health.


Medication for SAD typically includes antidepressants. It may take some trial and error to find the right antidepressant and dosage, so it’s important to communicate honestly with your provider about your experience with any new medication. Once you find the right one, your provider may recommend taking it every year—starting before your symptoms typically appear and ending around the time you usually start feeling better.

Light therapy

Light therapy, also called phototherapy, involves sitting in front of a light box or special lamp each morning to mimic natural outdoor light. This treatment is thought to alter the chemicals in your brain, regulating your circadian rhythms and improving your mood. Most people start seeing an improvement in SAD symptoms within one to two weeks of starting phototherapy.

If your provider thinks you can benefit from light therapy, they’ll give you specific guidelines for choosing a light therapy box. Typically, you want one that exposes you to 10,000 lux of light while producing as little UV light as possible.

Note: Light therapy boxes aren’t regulated by the FDA, so it’s important to work with your provider to find one that’s both safe and effective.

Can you prevent SAD?

Unlike many mental disorders, SAD is fairly predictable. Once you have a diagnosis, you know what to expect when fall and winter roll around each year. Though there’s no way to prevent symptoms altogether, you can take steps to prepare and prioritize your mental health before the depression sets in. These tips and tricks may help stave off the worst of your winter blues:

  • Stock up on candles, good books, and soft blankets to make your home extra cozy during the winter.
  • Spend time outdoors, especially when the sun is out.
  • Get regular exercise (outside when possible).
  • Address any existing health problems that may make SAD symptoms worse.
  • Start a fun new hobby.
  • Spend quality time with friends and family.
  • Enjoy new experiences, like exploring a new city or cooking something you’ve never tried before.
  • Keep your windows open during the day to let in the natural light.
  • Start journaling, meditating, or practicing gratitude.

Everyone has days when they don’t feel their best, but you should talk with your provider if you feel depressed or fatigued for days at a time. With treatment, you can minimize your SAD symptoms and start enjoying life year-round. This year, beat your seasonal depression by caring for your mental health and cultivating a winter experience that brings you joy.

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