Seasonal affective disorder (SAD) is a type of depression triggered by changing seasons. Most people with SAD begin to experience symptoms during the fall as the weather turns colder and the days grow shorter. The condition may worsen throughout the winter before ending in the spring. SAD is not simply a case of the “winter blues.” Rather, it’s a form of depression that affects your daily life and changes the way you think and feel. Fortunately, many treatment options are available.
Symptoms of seasonal affective disorder
As a type of depression, people who suffer from seasonal affective disorder may withdraw from social activities and lose interest in activities they usually enjoy. Other symptoms of SAD include:
- Extreme fatigue and lack of energy
- Difficulty concentrating
- Appetite changes
- Craving high-carb foods
- Weight gain
- Feeling hopeless or worthless
- Problems sleeping or oversleeping
- Thoughts of death or suicide
If you or a loved one has thoughts of suicide, call the National Suicide Prevention Lifeline at 800-273-8255. This national network of local crisis centers is available 24/7 and provides free, confidential emotional support to people in suicidal crisis or emotional distress.
Risk factors for seasonal depression
Seasonal affective disorder affects about five percent of the U.S. population, while 10 to 20 percent have a milder form of the condition. It’s more common in women than in men and occurs more frequently in young adults between the ages of 18 and 30. In fact, about 75 percent of people who get seasonal affective disorder are women.
People who live in northern climates or in parts of the world that experience decreased sunlight during the winter are more likely to suffer from SAD. It also tends to occur in those with other mental conditions, such as anxiety, attention deficit hyperactivity disorder (ADHD), depression, or bipolar disorder. In addition, a family history of mental health conditions increases your risk of developing SAD.
What causes seasonal affective disorder?
While the cause of seasonal affective disorder is unknown, many factors seem to play a role in developing the condition.
- Biological clock. Everyone has an internal clock that regulates hormones, mood, and sleep. Reduced exposure to sunlight during the fall and winter may cause this clock to shift and make it more difficult to regulate the hormones that affect moods and sleeping patterns.
- Brain chemicals. A neurotransmitter in the brain called serotonin plays a role in affecting mood and contributes to feelings of happiness. Sunlight helps regulate serotonin, and lack of sunlight can cause serotonin levels to fall, leading to mood changes and depression.
- Melatonin. A hormone called melatonin helps regulate sleep patterns. Lack of sunlight may disrupt the balance of melatonin in the body, which causes feelings of sluggishness and sleepiness.
- Vitamin D. Sunlight helps our bodies produce vitamin D, which boosts our serotonin levels. Reduced sunlight in the fall and winter can lead to a vitamin D deficiency and deplete serotonin levels.
How to treat seasonal affective disorder and seasonal depression
A number of treatment options are available for seasonal affective disorder. Depending on your specific situation, you may need a combination of treatments, including:
- Light therapy using a special lamp
- Cognitive behavioral therapy (CBT)
- Antidepressant medication
- Vitamin D supplements
For some people, simply spending time outdoors during the day and getting more sunlight can help improve the symptoms of SAD. Increasing the amount of sunlight that enters your home or office may also help.
Exposure to sunlight, even in the fall and winter, raises your risk of developing skin cancer, so always apply sunscreen 15 minutes before you go outside.
Light therapy for seasonal affective disorder
Before trying light therapy for SAD, ask your doctor if it’s right for you. The treatment requires a special lamp with a full-spectrum light bulb that is covered with a screen to block harmful ultraviolet (UV) rays. The light is about 20 times brighter than regular indoor light.
Morning light therapy work bests for most people and is less likely to cause insomnia.
- Choose a lamp that emits light at 10,000 lux
- Place the lamp two to three feet away from you
- Don’t look directly into the light
- Turn on the lamp for 15 to 30 minutes every morning
Light therapy often produces results within a few days, although it may take up to two weeks to reach the full benefits. Stopping light therapy may cause your symptoms to return, so healthcare providers recommend using light therapy through the entire winter.
Do not use light therapy if you have diabetes or certain eye conditions. If you take antibiotics or anti-inflammatory medications, ask your doctor if it’s safe for you.
Preventing seasonal depression
If you have seasonal affective disorder, you’re likely to get it every year, but there are steps you can take to manage the symptoms.
- Eat a healthy diet. The staples of a nutritious diet include vegetables, fruits, lean proteins, and whole grains. Comfort foods and sweet treats are okay in moderation, but try to choose options that are lower in saturated fat and added sugars, and limit your portion sizes.
- Make sure you’re getting enough vitamin D. Vitamin D deficiency due to lack of exposure to sunlight can worsen the symptoms of SAD, so eat foods rich in vitamin D, like fatty fish (such as trout, salmon, tuna, and mackerel), mushrooms, and milk fortified with vitamin D.
- Stay active. If you find yourself exercising less during the fall and winter, explore creative ways to fit physical activity into your daily routine. Moderate exercise, like a brisk walk or climbing stairs, can help you maintain a healthy weight, reduce anxiety, keep your blood pressure in check, and sleep better.
- Get the sleep you need. Exposing yourself to too much light in the evening, including the light emitted from smartphones, computer screens, and TVs, can slow down the release of melatonin, a hormone that regulates the sleep-wake cycle. If you have trouble sleeping, restrict screen time at night, and get up and go to bed at the same time of day regardless of the season. Discover nine tips for better sleep.
- Don’t isolate yourself. Although you may want to be alone, it can make your symptoms worse. Connecting with others and volunteering in your community can help you maintain your well-being and improve your mood.
- Limit or avoid alcohol. While alcohol may provide short-term relief, it can make the symptoms of SAD worse.
Mayo Clinic, Seasonal Affective Disorder (SAD)
Cleveland Clinic, Seasonal Depression (SAD)