What Is Seasonal Affective Disorder (SAD)? Symptoms, Causes and Treatment
Why winter months can impact mental health and mood
Why winter months can impact mental health and mood
The winter months can take a toll on moods and energy levels. Reduced sunlight is often a contributing factor.
While it’s normal to feel a little down or tired during this time of the year, symptoms that return around the same time each year may be signs of Seasonal Affective Disorder (SAD), sometimes called seasonal depression.
Seasonal affective disorder is a type of depression linked to changes in the seasons. It most often begins in the fall or winter and improves in the spring or early summer. With proper treatment and supportive lifestyle changes, symptoms can be effectively managed.
“If you experience persistent feelings of hopelessness or worthlessness or if your mood is interfering with work, family life or daily activities, it’s important to talk with your physician,” says Clark Bach, MD, an internal medicine physician at Scripps Coastal Medical Center Vista.
“SAD is a recognized medical condition. Don’t hesitate to reach out for medical expertise to help you get through these months if you need it,” Dr. Bach says.
What is Seasonal Affective Disorder?
Seasonal affective disorder is marked by a recurring seasonal pattern of depression.
The most common form is winter-pattern SAD, often called winter depression. A less common form occurs during the summer months.
In its most severe form, SAD shares symptoms with major depression, including:
- Feeling depressed most of the day, nearly every day
- Difficulty concentrating
- Changes in sleep or appetite
- Loss of interest in activities once enjoyed
- Feelings of hopelessness or worthlessness
- Thoughts of death or suicide
A defining feature of SAD is its timing. Symptoms typically:
- Begin in the fall
- Worsen during winter
- Improve or resolve in spring or early summer
While symptoms may ease naturally as seasons change, treatment can significantly reduce their severity and duration.
Who is most at risk for seasonal depression?
According to the National Institutes of Health seasonal affective disorder affects about 5% of adults in the United States, mainly in northern states. About 14% experience mild mood changes, often called “the winter blues.”
Those most at risk include:
- Young people
- Women
- People with a family history of depression or mood disorders
- People who live farther from the equator, where winter days are shorter and sunlight is limited
What causes Seasonal Affective Disorder?
The exact cause of SAD is not fully understood, but research suggests that reduced sunlight exposure plays a key role.
Less daylight can disrupt the body’s circadian rhythm or internal clock, which helps regulate sleep, mood and energy levels.
Seasonal changes may also affect the immune system, contributing to fatigue and low mood.
Reduced sunlight exposure can influence the body in several ways, including:
Serotonin imbalance: Less sunlight may interfere with serotonin regulation; a brain chemical linked to mood.
Melatonin changes: Longer nights can increase melatonin levels, leading to sleepiness and lower energy.
Vitamin D deficiency: Reduced sunlight may lower vitamin D levels, which are linked to mood regulation.
To be diagnosed with SAD, symptoms must follow a seasonal pattern and occur for at least two years in a row. This helps to tell it apart from other types of depression.
Common symptoms of winter-pattern SAD
People with winter depression may experience:
- Low energy or ongoing fatigue
- Sleeping more than usual
- Increased appetite or overeating
- Cravings for carbohydrates
- Social withdrawal
“If these symptoms persist, there are healthy and effective ways to counter the mood-dampening effects of winter,” Dr. Bach says.
Five ways to cope with winter depression
1. Improve nutrition, limit refined carbohydrates
People with SAD may crave sugary or starchy foods, which can worsen fatigue and mood swings.
“As the days grow shorter in winter, you may start craving comfort foods — simple carbohydrates like bread, pasta, sugary pastries and potatoes,” says Dr. Bach. “But the crash that often follows a sugar or carb-heavy binge can leave you feeling even worse than before.”
Dr. Bach recommends focusing on a balanced, nutrient-rich diet that supports both energy levels and mood, including lean proteins, whole grains and fruits and vegetables.
“Foods such as oatmeal, whole-grain bread, brown rice and bananas can boost feel-good serotonin levels without the sugar crash,” Dr. Bach says. “And foods rich in omega-3 fats — like oily fish, walnuts, soybeans and flaxseeds — may also help improve mood.”
2. Stay physically active – and spend time outdoors
Even when motivation is low, staying active can lift mood and boost energy. Regular exercise can help reduce SAD symptoms.
“For the greatest mood benefits, try exercising or being physically active outdoors during daylight hours,” says Dr. Bach. “Scheduling activity in the morning or afternoon can help release mood-boosting endorphins while also allowing your body to produce sunlight-driven Vitamin D.”
Mild to moderate daily exercise can make a meaningful difference. Activities, such as walking, gentle stretching, light yoga or simply moving more throughout the day can help.
“These rhythmic forms of exercise can put your mind into a more meditative state, which helps manage stress and bolster mood,” Dr. Bach says.
3. Consider light therapy
Light therapy, also known as phototherapy, is a common treatment for seasonal depression. It works by compensating for the reduced daylight in winter through daily exposure to bright, artificial light.
Light therapy involves sitting near a specially designed light box that emits bright light similar to natural sunlight while filtering out harmful ultraviolet (UV) rays. Most people use a light box for about 20 to 60 minutes each morning.
Before starting light therapy, talk to your doctor to see if it’s right for you. Light therapy boxes are wide available, but they are not approved by the Food and Drug Administration for treatment of SAD. Many doctors recommend them because research shows they can be effective and safe when used properly.
It’s also important to note that tanning beds are not a form of light therapy and should never be used to treat seasonal depression.
“Light therapy boxes work because the visible light enters the eyes indirectly and helps regulate mood-related brain chemicals,” Dr. Bach says. “These devices are also designed to filter out harmful ultraviolet rays that can increase the risk of skin cancer.”
While light therapy is generally safe, people with bipolar disorder or certain eye conditions should consult a doctor before starting treatment as it may trigger manic symptoms or cause eye discomfort.
4. Talk with your doctor about medication
For some people with moderate to severe SAD, antidepressant medications can be part of an effective treatment plan. Selective serotonin reuptake inhibitors (SSRIs) may be prescribed to help manage symptoms.
A physician can help determine:
- Whether medication is appropriate based on symptoms and medical history
- Potential benefits and side effects
- How long treatment may be needed
5. Try talk therapy
Your doctor may recommend cognitive behavior therapy (CBT) to help treat seasonal depression. CBT is a type of talk therapy that focuses on identifying and changing negative thought patterns and behaviors.
“CBT teaches people to challenge negative thoughts and incorporate more enjoyable activities into daily life during the winter months,” says Dr. Bach.
For example, reframing thoughts like “I can’t stand the darkness of winter” into a more balanced perspective, such as “I prefer summer and spring and though I dislike winter, I can manage it,” can help reduce stress.
CBT may also encourage planning small, fun activities each day, like listening to music, connecting with others or spending time with a pet.
When to seek help
If you experience symptoms of seasonal affective disorder, talk with a health care provider. SAD is treatable and early support can improve quality of life.
Seek immediate help if you experience:
- Ongoing or worsening depression
- Thoughts of self-harm or suicide
- Trouble functioning at work or home or in daily activities