How to Recognize the Signs of Seasonal Affective Disorder (SAD)

An expert explains the difference between seasonal depression and the ‘winter blues,’ and how to treat it.

Animation of changing seasons to help illustrate seasonal affective disorder and winter depression amid the pandemic

While some welcome the changing leaves of fall and fresh snow of winter, others find themselves having difficulty waking in the morning, experiencing daytime fatigue, eating more carbohydrates, and feeling a general sense of depression this time of year. There’s a name for this — seasonal affective disorder, or SAD — a type of depression that comes and goes with the seasons. Onset typically begins in late fall and early winter, when temperatures drop and days are shorter, and can continue through spring.

Health Matters spoke with Kimberly Kleinman, Psy.D. a senior psychologist at NewYork-Presbyterian/Columbia University Irving Medical Center, about ways to identify and treat SAD, and how to fight seasonal depression.

“Know yourself, pay attention to yourself, and trust yourself,” says Dr. Kleinman, who is also an assistant clinical professor of medical psychology (in psychiatry) at Columbia University Vagelos College of Physicians and Surgeons. “If you’re feeling like this isn’t just the winter blues, and it’s lasting for more than a couple of weeks, and it’s hard for you to get out of bed, pay attention to that and consult with a health care provider who can help you help yourself.”

Dr. Kimberly Kleinman, seasonal affective disorder expert

Dr. Kimberly Kleinman

What is seasonal affective disorder, or SAD?
Seasonal affective disorder is a form of depression, where people experience symptoms of depression in a seasonal pattern – typically in the fall or winter months when the weather is getting a little bit colder and there’s less light. Then, as the seasons change again, they will start to feel better, and their depressive symptoms will go down.

What are the symptoms of SAD?
Symptoms may be a sad mood, feelings of hopelessness or thoughts of self-harm. You might feel more tired with disruptions in sleep and notice irritability and changes in mood and appetite and find yourself eating more, especially carbohydrates. People with SAD may have problems making decisions or concentrating, or feel restless, and have other symptoms that impact relationships and ability to go to work or school.

How do you know it’s seasonal depression and not just the winter blues?
It’s more than just feeling sad or down. The Diagnostic and Statistical Manual of Mental Illnesses, or DSM-5, name for SAD is a major depressive disorder with seasonal pattern. The symptoms of depression are impacting a person’s life and daily functioning.

Are there any other signs you may have SAD?
People with seasonal depression tend to follow the same pattern each year, feeling depressed during the fall and winter, or less commonly, spring and summer, but feeling well the rest of the year. If you’ve experienced this pattern for at least two years in a row, it’s possible you may have seasonal depression.

What causes it?
It’s not fully understood but may have something to do with reduced amounts of sunlight affecting serotonin, the neurotransmitter that helps us regulate our moods, and melatonin, the hormone that makes us sleepy. Lower levels of serotonin may have a connection with an increased risk for depression. Melatonin naturally follows the rhythmic light pattern, kicking in toward the end of the day when it gets dark. And so, during winter with those longer durations of darkness, people with SAD may have increased melatonin, meaning they’re sleepier and more tired, which can also increase the risk of depression.

Serotonin and melatonin help maintain the body’s rhythm and night-day cycle. For people with SAD, these changes disrupt the normal daily rhythms, and they have a harder time adjusting to the seasonal changes, like the shorter days.

Your circadian rhythm, or the body’s biological clock, may also get disrupted by less sunlight, which can also lead to symptoms of depression.

How many people are affected by SAD?
Seasonal affective disorder is estimated to affect 5% of adults in the United States. An additional 10% may have mild cases. The disorder affects women four times more than men, and usually begins between the ages of 18 and 30, though children can suffer too. Those diagnosed with SAD experience major depression seasonally for at least two consecutive years. But there are significant geographic differences, especially in latitude since winter nights are hours longer in the north than in the south.

Who is most at risk for developing SAD?
We aren’t sure why, but women are more likely to suffer from SAD than men. And people with a history of depression or the seasonal pattern of even just feeling down are also more likely to experience the symptoms as well.

SAD is less common in young children and at puberty, there is an increase for girls, but not boys.

At what point is it necessary to see a doctor?
If you’re noticing that you’re feeling down and sleepier, and you’re having these symptoms, and they are lasting more than two weeks, you should reach out to your health care provider or therapist and let them know what’s going on. They may do a full clinical interview with you and discuss the seasonal pattern, the severity of the symptoms, what you’ve tried and what works to help with diagnosis and treatment recommendations.

How is SAD treated?
Light therapy — from a box that emits bright light, at the level of natural outdoor light shortly after sunrise — is the primary, best-investigated, and most successful intervention. It is a home-based treatment, recommended to be done immediately upon getting out of bed. People who find the light box effective find it effective very quickly and will usually see an improvement within a few weeks.

In addition, there are behavioral and routine things we can do to help depression, like getting up and moving around. Try to be regular with your eating and sleeping habits. Exercising is helpful for depression and mood. Another effective treatment would be a combination of psychotherapy and medication.

And even if it’s cold, try to get outside for at least 20 minutes to get some sunlight and be active. It’s easy to hunker down and turn down plans, but it’s important to go out. Make plans with friends, family and do things that you would normally do and try not to let the weather limit you, because all these interactions may help with your mood, in addition to other treatments.

Is taking vitamin D supplements a recommended therapy?
Vitamin D isn’t found to be directly linked to SAD. That said, these levels decline in winter both for people who experience SAD and those who don’t. The common cause is reduced outdoor daylight exposure. While there is no convincing evidence that Vitamin D is therapeutic for SAD, many North Americans do have low levels of Vitamin D and you can check with your health care provider to see if a supplement is recommended.

What’s the most important message you have for those suffering from SAD?
Educate yourselves and take responsibility for discussing SAD with your doctor or a mental health professional. You don’t need to suffer just because the days are shorter. Don’t hesitate to reach out, and we can help you understand it.

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