Mental Health Spotlight: Seasonal Affective Disorder

What Is Seasonal Affective Disorder?

Seasonal affective disorder is a type of depression that occurs only during a particular time of year.¹ For most people, SAD typically begins in the late fall or early winter and ends in the spring or early summer, with January and February being the most difficult period. The American Psychiatric Society estimates that symptoms can usually last up to 40 percent of the year.

What Causes Seasonal Affective Disorder

Though SAD can be caused by a number of factors, there seems to be one common denominator: a lack of sunlight. Winter’s shorter, gloomier days just don’t provide enough sunlight to keep your mood in good spirits, and that can take a toll on your mental health. Other contributors that can increase your risk for SAD include:^{2, 3}

Where you live. Your latitude may have something to do with your mood. The farther north you live, the more susceptible you are to bouts of winter depression.⁴ That’s because northern latitudes get much less sunlight this time of year than the southern ones do. For example, on the Winter Solstice (aka the shortest day of the year), Seattle sees only about 8.5 hours of daylight, whereas Miami gets 10.5.

Gender. Women are more likely to experience seasonal affective disorder than men are. In fact, one study suggests that females are more than three and a half times more likely than males to have SAD.⁵

Family history. Like so many illnesses, seasonal depression tends to run in families. If your family has a history of SAD or another form of depression, then you’re more likely to have it as well.

Age. Your age may also put you a risk of SAD. Young adults aged 18 to 30 are more likely to experience this type of depression than their older counterparts.

The Symptoms of SAD

Some of the most common seasonal affective disorder symptoms include:

• Depression
• Low energy
• Sluggishness
• Oversleeping
• Loss of interest in once-enjoyable activities
• Irritability or anxiety
• Changes in appetite and weight
• Difficulty concentrating
• Feelings of hopelessness or worthlessness

How to Treat Seasonal Affective Disorder

Seasonal depression can make it hard to stay motivated, especially when it comes to healthy choices. Fortunately, you don’t have to go out of your way to improve your disposition. There are plenty of simple steps you can take each day to feel better.

Get as much natural sunlight as possible. If the sun is shining, get outside and soak up as many rays as possible. And do it without your shades on. Wearing sunglasses can significantly reduce the amount of sunlight that reaches your brain, lowering its antidepressant effects and increasing the risk of winter depression.⁶ This is because sunlight, even in small doses, can help boost serotonin levels and improve your mood.

Try light therapy. There’s a good chance you’re going to experience gloomy weather for a prolonged period this winter. So if the sun just won’t shine, give light therapy a shot. Bright light therapy, which can be done at home with a special light therapy lamp, has been used to effectively treat seasonal affective disorder for decades.⁷

Exercise regularly. Physical activity is a powerful way to fight SAD.⁸ Indeed, regular exercise can be as effective as prescription antidepressants for battling depression of any kind. Exercise boosts serotonin, norepinephrine, and other feel-good brain chemicals while reducing inflammation. For the most SAD-busting workout, moderate- and high-intensity resistance training appears to provide the most mental benefit.⁹ And if you’re able to be active outdoors in the sun, even better.

Eat healthy. Good dietary habits don’t just help prevent issues like high cholesterol, diabetes, and digestive disorders; they can also keep you in a better mood. Eating a healthy diet, like a Mediterranean-style eating plan, has been shown to protect against depression.¹⁰ More specifically, a 2018 study showed exactly which foods provide the biggest bang for your buck. Seafood, such as oysters, mussels, and salmon, and plant foods, including leafy greens, lettuces, peppers, and cruciferous vegetables, were determined to have the most antidepressant effects.¹¹

Supplement with synbiotics. Give your mood a boost by adding a synbiotic supplement to your daily regimen. Synbiotics combine probiotics with prebiotics, which act as food for the beneficial bacteria in your gut and help them grow. While probiotics—and synbiotics—are typically used to support healthy digestion and gut health, they are also effective at improving symptoms of seasonal depression. That’s because the gut is connected to the brain via the gut-brain axis. A recent preliminary study suggests that synbiotics can help relieve the negative feelings that accompany stress.¹² What’s more, another study shows that synbiotics can improve not only stress but also anxiety and depression in overweight or obese people.¹³

All in all, it’s completely normal to have some days when you feel a bit “off” or a little sad. But if you feel down for days or weeks at a time this winter and can’t get motivated to do things you normally enjoy, try a few of these easy-to-incorporate tips to improve your mood and overall mental well-being.

1. Fonte A. Seasonal sensitivity and psychiatric morbidity: study about seasonal affective disorder. BMC Psychiatry. 2021;21:317.
2. Drew EM. Seasonal affective disorder and engagement in physical activities among adults in Alaska. International Journal of Circumpolar Health. 2021;80:1.
3. Galima SV. Seasonal affective disorder: Common questions and answers. American Family Physician. 2020;102(11):668–72.
4. Kegel M. The prevalence of seasonal affective disorder (SAD) in Greenland is related to latitude. Nordic Journal of Psychiatry. 2009;63(4):331–5.
5. Lucht M. Gender differences in seasonal affective disorder (SAD). Archives of Women’s Mental Health. 1999;2:83–9.
6. Alpayci M. Sunglasses may play a role in depression. Journal of Mood Disorders. 2012;2(2).
7. Pjrek E. The efficacy of light therapy in the treatment of Seasonal Affective Disorder: A meta-analysis of randomized controlled trials. Psychotherapy & Psychosomatics. 2020;89(1):17–24.
8. Peiser B. Seasonal affective disorder and exercise treatment: a review. Biological Rhythm Research. 2009;40:1,85–97.
9. Singh B. Effectiveness of physical activity interventions for improving depression, anxiety and distress: an overview of systematic reviews. British Journal of Sports Medicine. 2023.
10. Lassale C. Healthy dietary indices and risk of depressive outcomes: a systematic review and meta-analysis of observational studies. Molecular Psychiatry. 2019;24(7):965–86.
11. LaChance LR. Antidepressant foods: An evidence-based nutrient profiling system for depression. World Journal of Psychiatry. 2018;8(3):97–104.
12. Lalitsuradej E. The effects of synbiotics administration on stress-related parameters in Thai subjects-a preliminary study. Foods. 2022;11(5):759.
13. Hadi A. Clinical and psychological responses to synbiotic supplementation in obese or overweight adults: A randomized clinical trial. Complementary Therapies in Medicine. 2019;47:102216.

This article is for informational purposes only. This article is not, nor is it intended to be, a substitute for professional medical advice, diagnosis, or treatment and should never be relied upon for specific medical advice.