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. “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.”
Seasonal affective disorder (SAD) is a type of depression that’s related to changes in seasons — SAD begins and ends at about the same times every year. If you’re like most people with SAD, your symptoms start in the fall and continue into the winter months, sapping your energy and making you feel moody. Less often, SAD causes depression in the spring or early summer. Some people may get a mild version of SAD known as the “winter blues.” It’s normal to feel a little down during colder months. You may be stuck inside, and it gets dark early.
- About 5% of adults in the United States experience SAD. It tends to start in young adulthood. SAD affects women more than men, though researchers aren’t sure why.
- About 75% of people who get seasonal affective disorder are women.
- About 10% to 20% of people in America may get a milder form of the winter blues.
Signs and symptoms of SAD may include:
- Feeling depressed most of the day, nearly every day
- Losing interest in activities you once enjoyed
- Having low energy
- Having problems with sleeping
- Experiencing changes in your appetite or weight
- Feeling sluggish or agitated
- Having difficulty concentrating
- Feeling hopeless, worthless or guilty
- Having frequent thoughts of death or suicide
Researchers don’t know exactly what causes seasonal depression. The lack of sunlight may trigger the condition in people who are prone to getting it.
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.