Seasonal Depression


What is seasonal affective disorder (SAD)?

Seasonal affective disorder (SAD) is depression that gets triggered by a change in seasons, usually when fall starts. This seasonal depression gets worse in the winter before ending in the spring.

Some people may get a mild version of SAD known as the “winter blues.” It’s normal to feel a little down during colder months. You may be stuck inside, and it gets dark early.

But full SAD goes beyond that — it’s a form of depression. Unlike the winter blues, SAD affects your daily life, including how you feel and think. Fortunately, treatment can help you get through this challenging time.

Can people get summer depression?

Some people get a rare form of SAD called “summer depression.” It starts in the late spring or early summer and ends in the fall.

How common is seasonal affective disorder (SAD)?

About 5% of adults in the United States experience SAD. It tends to start in young adulthood. SAD affects women more than men, though researchers aren’t sure why. About 75% of people who get seasonal affective disorder are women.

About 10% to 20% of people in America may get a milder form of the winter blues.

Who is at risk for seasonal affective disorder (SAD)?

SAD is more common in younger people and women. You’re also at higher risk if you:

  • Have another mood disorder, such as major depressive disorder or bipolar disorder.
  • Have relatives with other mental health conditions, such as depression or schizophrenia.
  • Live at high latitudes (farther north of the equator), such as Alaska or New England.
  • Live in cloudy regions.

People with seasonal affective disorder may also have other mental conditions, such as:

Symptoms and Causes

What causes seasonal affective disorder (SAD)?

Researchers don’t know exactly what causes seasonal depression. The lack of sunlight may trigger the condition in people who are prone to getting it. The theories suggest:

  • Biological clock change: When someone has less exposure to sunlight, their biological clock shifts. This internal clock regulates mood, sleep and hormones. When it changes, people may have trouble regulating their moods.
  • Brain chemical imbalance: Brain chemicals called neurotransmitters send communications between nerves. These chemicals include serotonin, which contributes to feelings of happiness. People at risk of SAD may already have less serotonin activity. Since sunlight helps regulate serotonin, the lack of winter sun can make the situation worse. Serotonin levels can fall further, leading to mood changes.
  • Vitamin D deficit: Serotonin also gets a boost from vitamin D. Since sunlight helps us produce vitamin D, less sun in the winter can lead to a vitamin D deficiency. That change can affect serotonin and mood.
  • Melatonin boost: Melatonin is a chemical that affects sleep patterns. The lack of sunlight may stimulate an overproduction of melatonin in some people. They may feel sluggish and sleepy during the winter.
  • Negative thoughts: People with SAD often have stress, anxiety and negative thoughts about the winter. Researchers aren’t sure if these negative thoughts are a cause or effect of seasonal depression.

What are the symptoms of seasonal affective disorder (SAD)?

SAD is a type of depression, rather than a separate disorder. So people who have seasonal affective disorder may have signs of depression, including:

  • Sadness.
  • Anxiety.
  • Carbohydrate cravings and weight gain.
  • Extreme fatigue and lack of energy.
  • Feelings of hopelessness or worthlessness.
  • Inability to concentrate.
  • Irritability.
  • Limbs feeling heavy.
  • Loss of interest in usual activities, including withdrawing from social activities.
  • Sleeping more.
  • Thoughts of death or suicide.

People who have summer SAD may experience:

  • Agitation and restlessness.
  • Anxiety.
  • Decreased appetite and weight loss.
  • Episodes of violent behavior.
  • Trouble sleeping.

Diagnosis and Tests

How is seasonal affective disorder (SAD) diagnosed?

If you have symptoms of SAD, don’t try to diagnose yourself. See a healthcare provider for a thorough evaluation. You may have a physical issue that’s causing depression. But many times, seasonal affective disorder is part of a more complex mental health issue.

Your provider may refer you to a psychiatrist or psychologist. These mental health professionals talk to you about your symptoms. They consider the pattern of symptoms and decide if you have seasonal depression or another mood disorder. You may need to fill out a questionnaire to determine if you have SAD.

What tests will I need to diagnose seasonal affective disorder (SAD)?

There’s no blood test or scan to diagnose seasonal depression. Still, your provider may recommend testing to rule out other conditions that cause similar symptoms.

What are the criteria for a seasonal affective disorder (SAD) diagnosis?

Your provider may diagnose you with SAD if you have:

  • Symptoms of major depression.
  • Depressive episodes that occur during specific seasons for at least two consecutive years.
  • Depressive episodes that happen more frequently during a specific season than during the rest of the year.

Management and Treatment

How is seasonal affective disorder (SAD) treated?

Your provider will talk to you about treatment options. You may need a combination of treatments, including:

  • Phototherapy: Bright light therapy, using a special lamp, can treat SAD.
  • Cognitive behavioral therapy (CBT): A type of talk therapy called CBT can also effectively treat SAD. Research has shown that CBT produces the longest-lasting effects of any treatment approach.
  • Antidepressant medication: Sometimes, providers recommend medication for depression, either alone or with light therapy.
  • Spending time outdoors: Getting more sunlight can help improve symptoms. Try to get out during the day. Also increase the amount of sunlight that enters your home or office.
  • Vitamin D: A vitamin D supplement may help improve symptoms.

How does light therapy work?

To use light therapy, or phototherapy, you get a special lamp. It has white fluorescent light tubes covered with a plastic screen to block ultraviolet rays. The light is about 20 times brighter than regular indoor light. The intensity of light emitted should be 10,000 lux.

To use phototherapy, don’t look directly into the light. Place the lamp about 2 or 3 feet away while you read, eat or do other activities.

What time of day should I use light therapy?

When you use light therapy may impact how effective it is. Morning light therapy seems to work better. Plus, using it later in the day may cause insomnia. Many health professionals recommend 10,000 lux for 15 to 30 minutes every morning.

How long will it take light therapy to work?

People who use a lamp for SAD often see results within two to four days. It may take about two weeks to reach the full benefits.

How long do I use light therapy for?

Healthcare providers often recommend using light therapy through the entire winter. SAD symptoms can return quickly after stopping light therapy. Continuing to use the therapy can help you feel your best throughout the season.

Is light therapy safe?

Light therapy is typically safe and well-tolerated. But you may need to avoid light therapy if you:

  • Have diabetes or retinopathies: If you have diabetes or a retina condition, there’s a potential risk of damaging the retina, the back of your eye.
  • Take some medications: Certain antibiotics and anti-inflammatories can make you more sensitive to sunlight. Light therapy can then cause harm.
  • Have bipolar disorder: Bright light therapy can trigger hypomania or mania, uncontrolled boosts in mood and energy level. People with bipolar disorder need medical supervision to use light therapy.

What are the side effects of light therapy?

You may experience:

Can I use a tanning bed instead of light therapy to treat seasonal affective disorder (SAD)?

Don’t use tanning beds to treat SAD. Tanning beds do generate enough light, but they can cause other harm. They produce a high amount of UV rays that can hurt your skin and eyes.

What type of antidepressants can help with seasonal affective disorder (SAD)?

Medications called selective serotonin reuptake inhibitors (SSRIs) can treat SAD. They improve mood by regulating serotonin levels in your body.

Another approved antidepressant called bupropion comes as an extended-release tablet. It can prevent seasonal depression episodes when people take it daily from fall to early spring.


Can I prevent seasonal affective disorder (SAD)?

You may not be able to prevent the first episode of SAD. But once your provider has diagnosed you with seasonal depression, you can take steps to help keep it from coming back:

  • Use your light box: Start using light therapy at the beginning of fall, before you feel SAD symptoms.
  • Get out: Spend time outside every day, even if it’s cloudy. Daylight can help you feel better.
  • Eat a well-balanced diet: Even though your body may crave starchy and sweet foods, stick to nutritious choices. A healthy diet with enough vitamins and minerals can give you the energy you need.
  • Exercise: Try to get 30 minutes of exercise, three times a week.
  • See friends: Stay involved with your social circle and regular activities. They can provide support during the winter months.
  • Find help: Consider seeing a mental health professional who’s trained in CBT. This treatment can be very effective for seasonal affective disorder.
  • Consider medications: Talk to your healthcare provider about taking an antidepressant. Medications can help if your symptoms are severe or if they continue after other treatments. In some cases, taking the medication before SAD begins can prevent episodes.

Talk to your healthcare provider to find out if starting treatment early, as a preventive measure, is right for you.

Outlook / Prognosis

What’s the outlook for people with seasonal affective disorder (SAD)?

The outlook is positive. Treatments are available for SAD. People who get the right diagnosis and combination of treatments can find relief from symptoms. Talk to your healthcare provider to figure out the treatment that will work best for you.

Can seasonal affective disorder (SAD) come back?

People who are prone to seasonal affective disorder can get it every year. But you can take steps to prevent or lessen symptoms.

Living With

How can I best take care of myself if I have seasonal affective disorder?

Talk to your healthcare provider. By planning ahead, you can manage your symptoms and feel your best.


  • Stick to your treatment plan: If you have medications or a lamp for SAD, use them as directed. Follow up with your healthcare provider if you don’t see an improvement in your symptoms.
  • Care for yourself: Eat a well-balanced diet. Get enough sleep. Exercise regularly. Try to manage stress, perhaps by talking to a counselor or therapist.
  • Plan ahead: Make a plan for what you’ll do if your symptoms get worse. If you notice signs of depression, take action. It might help to plan a lot of activities during these months. Having a busy schedule keeps you from hunkering down at home.
  • Start treatment early: Talk to your healthcare provider about preventive treatment. If you know your symptoms start in October, consider starting treatment in September.


  • Isolate yourself: Being alone can make your symptoms worse. Even though you may not feel like going out or being social, try to reach out to friends and loved ones.
  • Use alcohol or drugs: They might make symptoms worse. And they can interact negatively with antidepressants.

When should I see my healthcare provider about seasonal affective disorder (SAD)?

If you think you have symptoms of seasonal depression or another mood disorder, see your healthcare provider. Your provider will want to rule out another condition or illness that may be causing these symptoms.

When should I go to the emergency room?

If you or a loved one has suicidal thoughts, get help. Call your provider, go to an emergency room, call 911 or call the National Suicide Prevention Lifeline, at 800.273.8255. This national network of local crisis centers provides free, confidential emotional support to people in suicidal crisis or emotional distress. It’s available 24/7.

What should I ask my healthcare provider?

If you have SAD, ask your provider:

  • What treatment is best for me?
  • How can I prevent depressive episodes?
  • Will light therapy work?
  • Should I take an antidepressant?
  • When should I start treatment?
  • How long should my treatment continue?
  • What can I eat (or should avoid eating) to improve my symptoms?
  • What else can I do to feel better?

A note from Cleveland Clinic

Seasonal affective disorder (SAD) is a type of depression that happens every year during a specific season, usually winter. Symptoms can include a lack of energy and feelings of hopelessness. Fortunately, there’s treatment for seasonal depression. Talk to your healthcare provider. The provider may recommend a special lamp for SAD. The lamp emits bright light to improve symptoms. Antidepressants and talk therapy can also provide relief. If you’ve had seasonal depression in the past, talk to your provider about starting treatment before symptoms begin.

Last reviewed by a Cleveland Clinic medical professional on 12/07/2020.


  • American Academy of Family Physicians. Seasonal Affective Disorder. ( Accessed 12/22/2020.
  • American Psychiatric Association. Seasonal Affective Disorder (SAD). ( Accessed 12/22/2020.
  • National Institute of Mental Health. Seasonal Affective Disorder. ( Accessed 12/22/2020.

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