Seasonal Depression: SAD Causes and How to Manage

“A big, common misconception about SAD is that it’s just the ‘winter blues,'” said Kelly Rohan, professor of psychology and clinical psychologist at the University of Vermont. As the days grow grayer and colder, and the holidays are upon us, it’s not uncommon to experience a temporary feeling of discomfort, fatigue, or stress. But seasonal affective disorder is much more serious — a form of clinical depression, said Dr. Rohan – with symptoms that can last longer and come and go with the seasons.

According to the National Institute of Mental Health, you may have seasonal affective disorder if you have specific symptoms that start and stop in specific months and that have lasted for at least two consecutive years. These include near-constant and daily feelings of depression, loss of interest in activities you used to enjoy, changes in your appetite or weight, sluggishness and low energy, trouble falling asleep or staying asleep during the day, or even thoughts of death or suicide.

Most people with seasonal affective disorder have winter-pattern SAD (or seasonal affective disorder), in which symptoms begin in late fall or early winter and resolve in spring and summer. But SAD can also occur during the spring and summer months, called summer pattern SAD (or summer depression).

SAD is much more common in women than men and in northern regions of the United States – like Alaska or New England – than in southern regions like Florida. It can also sometimes run in families.

“People may not realize how severely affected someone with SAD is,” said Dr. Paul Desan, psychiatrist at the Yale School of Medicine. For some people, he added, “life just wraps itself up for half the year.”

For people with winter SAD, it’s shorter, darker days that trigger depressive symptoms, said Dr. Rohan. But experts don’t know exactly why this happens.

A leading theory has to do with a biological clock shift. Normally, the body produces melatonin at night, which promotes sleep. When melatonin levels decrease as sunrise approaches, it helps people wake up. But if you suffer from Winter SAD, melatonin peaks later and lasts longer into the morning, making it harder to wake up and leaving you tired and groggy. Because you don’t reach peak wakefulness until later in the day, it’s harder to fall asleep when evening comes — perpetuating a cycle of insomnia, insufficient sleep, and fatigue, and worsening depressive symptoms.

Most people who are prone to SAD most likely always feel down, said Kathryn Roecklein, associate professor of psychology at the University of Pittsburgh. But in winter, light levels drop below a threshold and things suddenly become unbalanced.

There’s also some evidence that the negative anticipation of shorter days — for example, thinking “I just don’t function well in the winter” or “I’m going to feel bad soon,” said Dr. Roecklein – can be combined with biological effects to create a self-fulfilling prophecy.

While this can vary from person to person, SAD symptoms can last for quite a while — up to five months for some, said Dr. Lily Yan, Associate Professor of Psychology at Michigan State University.

Most people with winter SAD will notice symptoms between October and November, said Dr. Rohan. However, if you live in parts of the country where people are more susceptible, you might notice them earlier in the fall. Stressful life events, such as work instability or the loss of a loved one, can also trigger depressive episodes earlier than usual.

The most severe symptoms tend to appear in January and February, said Dr. Yan. Some experts believe this is due to the accumulated effects of SAD over time, she said. The longer the symptoms persist, the worse they become. But people tend to feel better when spring and early summer are over.

Symptoms of summer pattern SAD, which is much less common, usually begin in the spring and end around the beginning of the fall.

The good news, experts say, is that there are several evidence-based ways to find relief.

Bright light therapy

“Treatment with bright light first thing in the morning improves dramatically for the vast majority of people with seasonal depression,” said Dr. Desan. To do this, sit in front of a light therapy box that mimics outdoor light for about 30 minutes each day right after waking up, early in the morning is best. This should stimulate your body to produce the right hormones to increase your alertness and alertness to get you through the day, said Dr. Desan.

Just make sure you use it properly. If you don’t use it soon enough, it might not work; and if you use it too late in the day, it could make insomnia worse, said Dr. Rohan. Most experts recommend using light therapy lamps before 8am

Lots of lamps out there won’t do you any good, said Dr. Desan. When you’re looking for a light therapy lamp, you want one that advertises 10,000 lux of brightness — the equivalent of a bright summer morning. A good light therapy lamp should also be “full-spectrum,” he said, meaning it emits light that closely mimics natural morning sunlight. Unfortunately, it’s difficult to know exactly what you’re getting as light therapy lights aren’t regulated. As a guide for buyers, the lab of Dr. Desan at Yale clinically tested a number of lamps and listed his recommendations on his website.

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