Sunlight can affect your mood in a variety of ways. Sunny weather can put a smile on your face and improve your outlook, while a sky full of clouds can put a damper on your whole day.
Some people are more sensitive than others to seasonal changes in daylight hours. Seasonal affective disorder (SAD) is a form of depression that affects people who are sensitive to less sunlight. Most people experience SAD symptoms in the fall and winter months.
Anyone can experience SAD, but it’s more common in:
- People who live far from the equator, where daylight hours in the fall and winter are very short.
- People between the ages of 15 and 55 who are at a higher risk of getting SAD than those who are older.
- People who have a close relative with SAD.
People with SAD have a pattern of depression symptoms, including:
- Lack of motivation.
- Reduced ability to experience joy.
- Poor concentration.
- Changes in appetite.
- Insomnia or sleepiness.
- Low energy.
- Suicidal thoughts and behaviors.
SAD symptoms follow a seasonal pattern, generally occurring during the fall and winter months when we are exposed to less sunlight. Many people commute to work in the dark and travel home in near or complete darkness, which can increase symptoms. SAD symptoms usually improve with the arrival of spring.
SAD is more than a case of the “winter blues.” The symptoms of SAD, like other forms of depression, can make daily life difficult. SAD affects an estimated 10 million Americans, or about 6% of the population. Another 10 to 20% may have mild forms of SAD they don’t report.
SAD is more common in the northern parts of America. For example, SAD is seven times more common in Washington state than in Florida. Because of cloud cover, those living in western Pennsylvania may experience higher levels of SAD.
Reasons for Seasonal Changes in Mood
The cause of SAD is not clear. When the seasons change from summer to fall or winter, people may experience a shift in their internal biological clock (circadian rhythm). This change may lead to symptoms of SAD. Lack of daylight also can affect your body’s production of melatonin, a hormone that helps control the body’s internal clock and sleep cycle.
SAD has been associated with low levels of vitamin D, triggered in the winter months by shorter daylight hours and less sunlight. Other factors, such as not being able to enjoy favorite outdoor activities, may contribute to SAD.
What to Watch For
For some people, seasonal changes in mood can interfere with their daily activities and well-being. People living with SAD experience depressive symptoms that occur annually during fall and/or winter months. These symptoms can include:
- Sleeping a lot but still feeling tired.
- Craving sweets or carbs.
- Having a lack of energy.
- Losing interest in activities you enjoy.
- Having trouble concentrating.
- Feeling sad, grumpy, irritable, or anxious.
Talk to your doctor if you experience these symptoms because SAD can be treated.
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Mood-Boosting Treatments for SAD
- Light therapy is usually the first choice of treatment for SAD. Regular use of light therapy for 30 to 60 minutes each day can help ease the symptoms of SAD. This treatment is most effective if done before sunrise or right after sunset. Check with your mental health care provider before trying light therapy, especially if you have bipolar disorder.
- Antidepressants and vitamin D supplements may help with SAD symptoms.
- Counseling is a common treatment for SAD. Cognitive-behavioral therapy can help you learn what causes SAD, how to manage your symptoms, and how to prevent future episodes.
See your primary care provider or mental health specialist for guidance on using light therapy, selecting an antidepressant to treat SAD, or finding a therapist.
Daily Ways to Boost Your Mood
Whether you have SAD or a lack of light has just made you “blue,” here are a few simple ways to perk yourself up every day:
- Go outside. Get some fresh air. Take a short walk, especially on sunny days.
- Brighten your workspace. Open the blinds or turn on more lights. The more exposure you get to sunlight or bright lights indoors, the better you’re likely to feel.
- Think spring! SAD and “winter blues” are usually temporary. Try to remember that when spring arrives, your mood should start to lift.
If you or someone you love is struggling with symptoms of SAD, depression, addiction, or another mental illness, UPMC Western Psychiatric Hospital can help. We offer a wide array of behavioral health services for children and adults and provide cutting-edge programs and compassionate care for all types of psychiatric conditions and mental and behavioral health needs. Call us at 412-624-1000 or 1-877-624-4100 (toll-free).
If you live in Allegheny County and need immediate mental health care or counseling, call the free 24/7 resolve Crisis Services hotline at 1-888-796-8226 or visit the walk-in center at 333 North Braddock Ave., Pittsburgh, PA 15208.
Editor's Note: This video was originally published on , and was last reviewed on .
UPMC Western Psychiatric Hospital is the hub of UPMC Behavioral Health, a network of community-based programs providing specialized mental health and addiction care for children, adolescents, adults, and seniors. Our mission is to provide comprehensive, compassionate care to people of all ages with mental health conditions. UPMC Western Psychiatric Hospital is a nationally recognized leader in mental health clinical care, research, and education. It is one of the nation’s foremost university-based psychiatric care facilities through its integration with the Department of Psychiatry of the University of Pittsburgh School of Medicine. We are here to help at every stage of your care and recovery.