What is seasonal affective disorder?
Seasonal affective disorder (SAD) is a type of major depression affecting roughly 5 percent of Americans that comes and goes with the seasons. This condition, sometimes referred to as the “winter blues,” typically starts in the late fall as the sky gets gloomy and the temperature drops. Some people experience SAD in the spring or summer, but SAD during these seasons is much less common.
Carly McCord, PhD, clinical associate professor in the Texas A&M School of Medicine Department of Psychiatry and director of Texas A&M Health Telebehavioral Care, explains SAD and recommends ways to manage it.
What are the signs and symptoms of SAD?
Because seasonal affective disorder is a type of major depression, the signs and symptoms are much the same for each condition. Therefore, to be diagnosed with SAD, a person must first meet the criteria for major depression, and the depression symptoms must follow seasonal patterns for at least two years.
For instance, a person whose depression comes in random waves throughout the year probably does not have SAD. But a person who experiences depression every year from October to February probably does.
Although SAD symptoms and the symptoms of major depression overlap, according to the National Institute of Mental Health, some are more or less common based on the season:
Feeling depressed most of the day, nearly every day
Feeling hopeless or worthless
Having low energy, especially for wintertime SAD
Losing interest in activities
Having problems with sleep: Wintertime SAD tends to cause hypersomnia, or excessive sleeping, while summertime SAD tends to cause insomnia
Experiencing changes in appetite or weight: Wintertime SAD tends to cause overeating, weight gain and a craving for carbohydrates, while summertime SAD tends to cause poor appetite
Feeling sluggish or—alternatively—agitated, restless or anxious
Having difficulty concentrating
Social withdrawal, especially for wintertime SAD
Episodes of violent behavior, especially for summertime SAD
Having frequent thoughts of death or suicide
When identifying SAD through psychological evaluation, a doctor will determine if a patient has enough of these symptoms and other behavior patterns to warrant the diagnosis.
McCord notes, however, that feeling glum as the weather changes or having some of these symptoms does not necessarily mean a person has SAD—or any type of depression for that matter.
“You don’t get a diagnosis unless it is significantly impairing your functioning,” McCord explained. “Most people may experience low mood with gloomy weather, but that doesn’t mean it’s a diagnosis of depression or seasonal affective disorder.”
Impaired functioning is different for everyone, McCord said. Some people may struggle with work or school, while others could have difficulty socializing and withdraw from social interaction altogether.
What puts you at an increased risk of having SAD?
Although the exact cause of seasonal affective disorder is unknown, research has determined what attributes increase a person’s risk of developing this disorder. Based on current research, many of these risks are out of a person’s control.
For example, women are four times as likely to be diagnosed with SAD compared to men. Likewise, people who already have depression or have a family history of depression are more likely to develop SAD. Younger adults are also at an increased risk, with SAD being reported in both children and teenagers.
One way people can decrease their risk of developing SAD, however, is by living closer to the equator. In fact, only 1 percent of people who live in Florida experience SAD, while 9 percent of people in New England or Alaska have SAD. Some research suggests this effect of location could be related to skin pigmentation or vitamin D production, but more studies are needed to determine exactly how these factors contribute to SAD.
What can you do about SAD?
The four major treatments for seasonal affective disorder are medication, light therapy, psychotherapy and vitamin D supplementation, all of which can be used separately or in combination.
In addition to these treatments, McCord said, “Self-care is a recommended coping mechanism.” Some ways to practice self-care include:
Exercising
Eating healthy foods
Getting good sleep
Spending time with friends
Engaging in spirituality
Volunteering
Practicing gratitude
McCord emphasized that these self-care activities aren’t just for people with SAD, though. “Our environment influences us, and we have the ability to choose how we respond to that,” she said.
Originally published Jan. 7, 2020, updated Dec. 7, 2022.