Major Depressive Disorder with Seasonal Pattern (formerly called Seasonal Affective Disorder, or SAD)

Medically Reviewed by Smitha Bhandari, MD on April 01, 2022
5 min read

"Claire" began her sophomore year in high school eager to make new friends and committed to doing well in her classes. Then, as winter approached and the days grew shorter, Claire noticed that she needed more sleep than usual. Even after sleeping more, she had no energy and felt fatigued, moody, and depressed.

When she tried to write articles for the school paper, something that normally came easy for her, Claire had trouble concentrating. She started to miss deadlines. When it came time to print the newspaper, Claire had no articles to turn in. Over the next two months, friends stopped calling her. When Claire complained that no one invited her to sit with them at football games or attend weekend sleepovers, her parents became concerned.

Over the winter break, Claire had an appointment with her doctor. Claire told her doctor how tired she felt. She said no matter how much she slept, it was never enough to end her fatigue and sad mood. She also mentioned that she had gained weight since August, and that her appetite for carbs, especially chips and cookies, had greatly increased.

After doing a physical exam, Claire’s doctor ruled out other problems that cause fatigue and mood changes and diagnosed Claire with seasonal affective disorder, or SAD, a disorder now classified by the DSM-5 as Major Depressive Disorder with Seasonal Pattern.

Major depressive disorder with seasonal pattern, also referred to as winter or seasonal depression, is a syndrome with depression that starts and ends at the same time each year.

There are two types of this disorder - fall-onset and summer-onset. The fall-onset type, often called "winter depression," is more recognized. With less sunlight during these two seasons, some people who are predisposed to depression may be more likely to develop an episode. While the neurobiological causes of major depressive disorder with seasonal pattern are not well-established, it is thought that brain areas which regulate mood and operate using the neurotransmitter serotonin may not function properly. The National Institutes of Health estimates that more than 36 million Americans suffer seasonal depression that occurs in the fall.

Hormones manufactured in the brain that are affected by sunlight exposure may play a role in the development of major disorder with seasonal pattern and its symptoms of depressed mood, fatigue, carbohydrate cravings, and weight gain. Because foods high in carbohydrates (like chips, pretzels, and cookies) boost serotonin, it is thought that they have a soothing effect on the body and mind.

This disorder usually starts in young adulthood. It is more common in females than in males. Some teens with seasonal depression have very mild symptoms and just feel out-of-sorts or irritable. Others have more serious symptoms that interfere with relationships and schoolwork.

Because the lack of daylight during wintertime is related to major depressive disorder with seasonal pattern, it is seldom found in countries within 30 degrees of the equator, where the sun shines year round.

If you have seasonal depression that begins in the fall, like Claire’s, you might have the following symptoms:

  • Increased need for sleep
  • Increased appetite with carbohydrate craving
  • Weight gain
  • Irritability
  • Inability to concentrate
  • Problems with relationships (being sensitive to rejection)
  • A heavy feeling in arms or legs
  • The times you've been depressed during the fall/winter season outnumbering the times you've been depressed at other times over your lifetime

When seasonal depression begins in the spring or summer months, teens might have symptoms of depression such as weight loss, decreased need for sleep, and poor appetite.

There are different treatments for major depressive disorder with seasonal pattern, depending on the severity of the symptoms. If you have another type of depression or bipolar disorder, the treatment may be different.

Many doctors recommend that patients with this disorder try to get outside early in the morning to increase their exposure to natural light. If this is impossible during dark winter months, antidepressant medications and/or light therapy (phototherapy) may be used. Light therapy involves a full-spectrum light that is shined directly into your eyes.

With light therapy for seasonal depression, you sit about 2 feet from a bright light (about 20 times brighter than normal room lighting). You start with one 10- to 15-minute session per day. The time is then increased to 30-45 minutes a day, depending on your response. Some teens recover within days using light therapy; others take much longer.

If the symptoms don't stop, your doctor may increase the light therapy sessions to twice daily. Those who respond to light therapy are encouraged to continue until they can be out in the sunshine again in springtime. Light therapy alone may not be enough to relieve the seasonal depression; since it is a form of major depression, an antidepressant may be helpful.

Some researchers link major depressive disorder with seasonal pattern to the natural hormone melatonin, which causes drowsiness. Because light modifies the amount of melatonin in the human nervous system and boosts serotonin to the brain, light therapy has an antidepressant effect. When light strikes the eye's retina, a process in the body decreases the secretion of melatonin.

If you have feelings of depression, fatigue, and irritability that come at the same time each year, you may have a form of seasonal depression. Talk openly with your doctor about your feelings. Follow the doctor’s recommendations for lifestyle changes and/or treatment.

If your health care provider recommends light therapy, ask if they provide light boxes for patients with major disorder with seasonal pattern. You can also rent or purchase a light box, but they are expensive and health insurance companies do not usually cover them. While side effects are minimal with light therapy, be cautious if you have sensitive skin or have a tendency toward mania (feeling elated, excited, and unable to sleep).

Your health care provider might also suggest vitamin D supplementation.