A gloomy day can put many people in a bad mood. But for a small percentage of the population, a whole season can spiral into a serious depression called Seasonal Affective Disorder (SAD).
SAD strikes 1 to 10 percent of the population every year, according to a 2009 journal review in The Physician and Sportsmedicine.
The causes behind SAD are still unknown, but researchers are learning more about its biological clues. Reports of successful treatments using light therapy have led to a theory that dwindling daylight hours during fall and winter months interrupts some people's circadian rhythms causing depression, according to the National Institutes of Health (NIH).
"People tend to feel the symptoms in the autumn and more severely in the winter," said Dr. Victor Fornari, the director of child and adolescent psychiatry at the Zucker Hillside Hospital in Long Island, New York. "Typically it lifts in springtime."
The symptoms of SAD are the same as those that accompany depression. Hopelessness, unhappiness, irritability, a lack of interest in usual hobbies, difficulty paying attention, fatigue and withdrawing from friends and family are all symptoms of SAD, Fornari said.
While some forms of depression contribute to weight loss, SAD sufferers often have increased appetite and weight gain. SAD is also marked by daytime sleepiness and a lack of energy.
While many symptoms of SAD parallel symptoms of depression, SAD sufferers go through a yearly cycle of depressive symptoms followed by a time when they are free from symptoms.
"The first thing to recognize is having a day when you feel down is normal," Fornari said. "If you feel down for days at a time and you can't shake it, people should go see their primary care physician, especially if they have a disturbance in their sleep or if they're thinking about not wanting to live."
While sufferers may not experience SAD every year, they tend to have it 70 percent of the years. "So if you total up the amount of time of one's life it can be the same as major depression disorder," said Kathryn Roecklein, psychology professor at the University of Pittsburgh.
Diagnosis & tests
Doctors diagnose SAD through a series of questions about symptoms. Usually physical tests are only required to rule out other causes of depressive symptoms. Sometimes a psychological evaluation is needed for severe forms of SAD, according to the NIH.
SAD is considered a subtype of depression or bipolar disorder and can be difficult to distinguish from other psychological problems, according to the Mayo Clinic.
To be diagnosed with SAD, usually a person must meet the criteria in the Diagnostic and Statistical Manual of Mental Disorders, specifically: The person has experienced depression and other symptoms for at least two consecutive years during the same season every year. The periods of depression have been followed by periods without depression and there are no other explanations for the changes in mood or behavior.
Most people with SAD experience depressive symptoms in fall and winter. However, a rare form of SAD strikes people in the summer months.
Sufferers of summer onset SAD are more likely to have anxiety, irritability, weight loss, poor appetite and insomnia, according to the Mayo Clinic.
Treatment & medication
SAD treatments take different forms, because a person afflicted with SAD may respond better to one therapy than another individual.
Many people with SAD turn to "light therapy" from a light box, usually for 30 minutes in the morning. Its specialized fluorescent bulb mimics daylight.
"You sit a few feet away from the box. It can be very effective for people who have winter depression," Fornari said. "Often what they'll say is that, within a couple of days, they have more energy, that their mood is restored."
Doctors recommend SAD sufferers get medical advice before trying light therapy on their own. Working with an expert gives it the best chance of working, said Roecklein, because a doctor can prescribe how and when to use it and troubleshoot any issues.
A person trying light therapy should see their symptoms improve within three to four weeks if light therapy will help, according to the NIH.
Doctors may prescribe antidepressants for people suffering from SAD. A common drug prescribed for SAD is bupropion (Wellbutrin XL, Aplenzin), according to the Mayo Clinic. Several weeks may pass before a patient sees the full benefits of a medication.
Cognitive behavioral therapy (CBT) may also help people manage the depressive symptoms of SAD. During therapy sessions, people are asked to identify negative thoughts that cause them distress. Specialists then teach them skills that help manage and modify negative thoughts, Fornari said.
Researchers recently have learned that CBT, unlike light therapy and antidepressants, keeps working. "If you use it this year, your chances of having an episode as bad in the following winter are decreased," said Roecklein.
Light therapy, antidepressants, CBT or a combination of these approaches are the first-line treatments for treating people afflicted with SAD.
Doctors also recommend these individuals try to get as much natural daylight as possible by taking walks outside or sitting near windows. Exercising and staying connected with family and friends can also ease SAD symptoms, Fornari said.
Other people see improvements after trying mind-body therapies such as yoga, meditation and guided imagery, which helps people create an uplifting narrative combined with a positive image, Fornari said. [9 DIY ways to improve mental health]
According to the Mayo Clinic, some people have tried herbal remedies and dietary supplements to combat the symptoms of SAD; however, these remedies may interfere with medications and have unwanted side effects, so it's best to speak with a doctor before trying them.
One of the current challenges in treating SAD sufferers is the trial-and-error period to find the right primary treatment for an individual, but that waiting period could be eliminated based on current research.
The human retina functions differently in SAD, according to Roecklein. So, she and her team measure a SAD sufferer's retinal response to light to predict what treatment would be best for that individual. This "personalized medicine" could get relief to future sufferers faster.
- The American Psychiatric Association explains how SAD may develop.
- The NIH talk about the winter blues and treatment options.
- Learn about how SAD can affect teenagers.
If you have thoughts of suicide, get help right away. Call the toll-free National Suicide Prevention Lifeline at 1-800-273-TALK (8255).
This article was updated on Feb. 10, 2019 by Live Science Contributor Laura G. Shields.