Seeing friends was normally the highlight of Kendra Sands’ week. One night in January 2018, she had plans to meet two for dinner, but instead, Ms. Sands, who lives in Charlotte, N.C., crawled into bed. She wanted to go out, but she was stuck in a dark room, sobbing.
“I forced myself to put on different clothes, touch up my makeup and get in the car,” she said. “But driving to the restaurant, I realized hibernating in bed had been a pattern for weeks.”
Sands initially blamed PMS for the crying episodes, but after a month she still had no relief. After asking about her mental health pattern in previous years, Ms. Sands’ therapist eventually diagnosed her with seasonal affective disorder. “I knew I didn’t like the cold or dreariness of winter, but I never thought I had a form of depression,” Ms. Sands said.
According to Vaile Wright, senior director of health care innovation and practice directorate at the American Psychological Association, seasonal affective disorder (S.A.D.) is a type of major depression. What makes S.A.D. unique is its timing: “It has a distinct seasonal onset, typically in winter, and a spontaneous remission of symptoms,” she said.
S.A.D. patients experience classic depression symptoms: sadness, irritability, trouble concentrating, lack of interest in activities and increased sleep and appetite. It doesn’t have to be cold or snowy, people can experience S.A.D. in sunny climates like Florida or Southern California.
“The important consideration for all forms of S.A.D. is the effect of your surroundings,” said Dr. Amit Etkin, a professor of psychiatry and behavioral sciences at Stanford University. “The light you experience, how you interact with the world when you get up, and when you go to bed all have a disproportionate effect on your mood.”
Recognize S.A.D. in yourself.
Michael Terman, professor of clinical psychology at Columbia University and founder of the Center for Environmental Therapeutics, said it’s common to gain weight and feel lethargic in winter, but only around three percent of the population has S.A.D.
To be diagnosed, you need to experience at least five of nine clinical symptoms for at least two weeks, said Paul Desan, assistant professor of psychiatry at Yale School of Medicine. If you don’t, you could have subsyndromal S.A.D., a milder version Dr. Desan said people often call “winter blues.”
A distinct, seasonal pattern is key to recognizing S.A.D., feeling normal during spring and summer, then dwindling in energy and mood as days get shorter — almost like you want to hibernate. If you have a family member with S.A.D., you might be more likely to develop it, and Dr. Desan said the disorder is three times more common in women.
According to Dr. Terman, S.A.D. prevalence increases as you move north, until you hit 38 degrees (around Washington D.C.). Anywhere farther north is essentially equally affected at maximum severity. The likelihood also rises near the western edges of time zones, where dawn occurs later.
Experts agree it’s important to treat S.A.D. if you think you may have it. Here are some of the most common treatment methods they recommend.
Start with simple changes.
Many forms of depression, Dr. Wright said, benefit from changes to sleep schedule, a nutritious diet, exercise and social interaction. If you have S.A.D., put a winter spin on these behaviors.
For example, even if you want to sleep later, set an alarm each day so you can experience early-morning sunshine, which helps with S.A.D. symptoms. “Engaging actively in the world, as if you already had those rhythms, is a good way to help reset your circadian rhythm,” Dr. Etkin said.
What you do at night matters, too. Dr. Etkin suggests basic sleep hygiene like avoiding screens (and any artificial light). Try to keep your bedtime consistent — not too late — and avoid too much caffeine or alcohol, which can interfere with your quality of rest and ability to get up.
Try a light box.
Light activates a bodily signal that informs your cells what time of day it is. Morning light causes cortisol to spike, giving you energy. The time of that initial spike determines when your brain releases melatonin, a hormone that makes you sleepy before bedtime.
During winter, people often get less light in the morning and too much artificial light at night, which throws off these signals, affecting sleep and mood.
Light boxes — devices that produce artificial light similar to sunlight — may be an effective way to correct that. In a meta-analysis of 19 studies, bright light therapy was superior to placebo; another small study found 61 percent of light-therapy patients saw their depression symptoms ebb in four weeks.
There is some evidence that sitting in front of a 10,000-lux (the measure of light intensity) light box for 30-45 minutes every day around sunrise during fall and winter decreases S.A.D. symptoms. If you’re currently experiencing S.A.D. symptoms, it’s not too late to start. You can also begin treating next season’s symptoms in the fall.
As tempting as it is to hit the snooze button on weekends, Dr. Desan said your mood will start to sag again if you don’t do your treatment every day around sunrise, so build light therapy into your life. Most research-grade light boxes allow you to sit at arm’s length and move your head, so you should be able to eat breakfast, drink coffee or read.
An effective light box is usually at least $100, but not every option is equally effective. Of the 24 devices Dr. Desan tested in 2019, only seven met clinical criteria. The rest weren’t as effective as research-grade boxes.
According to Anna Wirz-Justice, professor emeritus in the Centre for Chronobiology at the University of Basel, in Switzerland, natural light isn’t only cheaper than a light box, it’s also brighter. Sunrise light is equivalent to 1,000 lux. A rainy morning provides around 10,000 lux, and snow on the ground is even brighter, at 50,000 lux.
Aim to go outside within 30 minutes after sunrise. “You don’t need to see the sun cross the horizon,” said Dr. Huberman. “What you’re looking for is the quality of light that happens when the sun is low in the sky.”
Duration depends on where you live and the weather. Dr. Huberman suggested around five minutes outside if it’s bright or 10-15 minutes if it’s cloudy. It’s OK to wear glasses or contacts, but skip sunglasses and never look at the sun directly.
See a psychotherapist.
Since 2000, Kelly Rohan, a psychology professor at the University of Vermont, has been conducting clinical trials comparing cognitive behavioral therapy (or C.B.T.) to light therapy. Her work suggests both treatments are effective for people with S.A.D. — especially after a new diagnosis. But when she followed people with S.A.D. for two winters, C.B.T. worked better than bright light therapy to prevent recurrences.
Dr. Rohan said C.B.T. may reduce symptoms more effectively because it provides long-term coping skills for changing negative thought and behavior patterns — whereas light therapy only works when you do it.
For Ms. Sands, the combination of lifestyle changes and psychotherapy made a significant difference in reducing her symptoms. But nothing helped more than naming the debilitating dip in her mood every winter. “Because I have a diagnosis, I can be proactive,” Ms. Sands said. “I don’t have to wait until spring to feel better.”
Ashley Abramson is a freelance writer based in Milwaukee, Wis.