What Is Seasonal Affective Disorder? Treatments and Symptoms

Medically Reviewed By Debra Rose Wilson, Ph.D., MSN, R.N., IBCLC, AHN-BC, CHT
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Seasonal affective disorder, also known as seasonal depression or SAD, typically occurs in the fall and winter months. Symptoms are similar to those of depression, including low mood, increased appetite, and oversleeping.

When does seasonal affective disorder occur?

woman wearing t-shirt, underwear and sweater bed in a darkened room
Thais Varela/Stocksy United

SAD typically occurs during fall and winter. Other names for the condition are winter depression and the “winter blues.”

People who experience SAD tend to have symptoms around the same time each year.

Can I get seasonal affective disorder in the summer?

While SAD is more likely to occur in the colder months, getting SAD during the spring and summer months is possible. However, this is less common.

How common is seasonal affective disorder?

Around 5% of people in the United States experience SAD, and 80% of people with SAD are female.

The average age at which people first experience SAD is around 18–30 years old.

What are the symptoms of seasonal affective disorder?

Symptoms of SAD can be mild or severe, and they can be similar to symptoms of depression.

Possible symptoms include:

  • feeling low
  • losing interest in activities or hobbies
  • increases in appetite, typically craving carbohydrates
  • changes to sleeping habits such as oversleeping
  • lack of energy
  • increased fatigue
  • inability to sit still
  • slow movements or speech
  • feelings of guilt or worthlessness
  • difficulties with concentrating or decision making

Symptoms of summer SAD are slightly different. Instead of sleeping too much and overeating, you may have a reduced appetite and difficulty sleeping.

How is seasonal affective disorder treated?

Treatments for SAD can include natural remedies, therapy, and medication.

Natural remedies

You can take steps to try and alleviate symptoms of natural remedies at home. Natural remedies can include:

  • getting as much natural light as possible by spending more time outdoors
  • working in light and airy environments where possible
  • spending time near windows when indoors
  • eating a healthy, balanced diet


Different types of therapy can help reduce SAD symptoms: light therapy and talking therapies, such as cognitive behavioral therapy (CBT).

Light therapy

Light therapy involves sitting in front of a SAD lamp, usually for around 30–60 minutes each morning. Some people believe that SAD lamps help increase the production of serotonin in the brain while also reducing melatonin production.

Recommended methods of SAD lamp therapy include lightboxes with filters that remove UV rays. The lack of UV rays helps prevent damage to the skin and eyes.

Side effects of SAD light therapy are rare. However, when they do occur, side effects can include:

Light therapy might not be suitable if you have sensitive eyes or are taking medications that make you sensitive to light. Contact your doctor before beginning light therapy.

Learn more about devices that can help with depression and low mood.

Talking therapies

Talking therapies such as CBT can help you to process the way SAD makes you feel while also providing you with some tools to better cope with symptoms when they arise.

Your doctor may refer you to a therapist alongside or instead of prescription medication.


Your doctor may prescribe antidepressants to help alleviate the depressive symptoms of SAD.

However, there is limited evidence of the efficacy of antidepressants in the treatment of SAD. More research is necessary to understand whether or not they are beneficial for alleviating related symptoms.

What causes seasonal affective disorder?

Medical professionals do not know the exact cause of SAD. However, there is a general belief that it occurs due to reduced levels of serotonin in fall and autumn. Your serotonin levels are lower when you get less exposure to sunlight.

Increased levels of melatonin may also contribute to SAD. Melatonin can affect mood and sleep patterns, and the brain creates more of it when it is dark. This means that melatonin levels are generally higher during the winter months with fewer daylight hours.

How is seasonal affective disorder diagnosed?

If you experience symptoms of SAD, your doctor will ask you questions to help diagnose the condition. They may ask when you experience these symptoms, how often you experience them, and if and when you have experienced them before.

They may also ask you questions about your lifestyle and personal history to determine if there are any other possible contributors to your change in mood.

SAD can be difficult to diagnose, as it shares many symptoms with other mental health conditions such as depression. Three main criteria for SAD are:

  • the depression occurring at the same time each year
  • the period of depression ending at the same time each year
  • the depression not regularly occurring throughout the rest of the year

If a doctor suspects that you are experiencing SAD, they may prescribe antidepressants. Alternatively, they may refer you to a mental health professional who can further assess your symptoms. The mental health professional will be able to offer therapeutic support, such as CBT.

What are the risk factors for seasonal affective disorder?

One risk factor for SAD is age, as it typically occurs in adulthood. You are more likely to experience SAD when you are between the ages of 18–30.

SAD is more likely to affect females than males (assigned at birth).

You may also be more likely to develop SAD if you live further away from the equator. This is because there is a higher amount of direct sunlight the closer you are to the equator.

SAD often occurs alongside other mental health conditions. These include:

You may be more likely to experience SAD if you have another mental health condition.

Learn more about how winter can affect depression.

Can I prevent developing seasonal affective disorder?

There are steps that you can take to help prevent symptoms of SAD from occurring. As SAD typically affects people around the same time each year, you will be able to take steps in advance.

For example, beginning light therapy or contacting your doctor about treatment before recurrent symptoms start can help you feel prepared and in control.

Other steps you can take to prevent or reduce the likelihood of SAD from occurring include:

  • getting as much natural sunlight as possible
  • spending more time outdoors
  • sitting or spending time near windows when indoors
  • using light therapy around the time you usually begin to experience symptoms


SAD causes you to feel low or depressed at the same time each year. It typically occurs during the fall and winter months, but it can also occur during spring and summer.

Treatments for SAD include light therapy, antidepressants, and talking therapies. You can also take steps to reduce SAD, such as getting enough sunlight and sitting near windows.

Contact your doctor if you experience symptoms of SAD. Diagnosing SAD can be difficult due to its similarities to other mental health conditions. However, they will be able to assess your symptoms and refer you to a mental health professional where necessary.

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Medical Reviewer: Debra Rose Wilson, Ph.D., MSN, R.N., IBCLC, AHN-BC, CHT
Last Review Date: 2022 May 31
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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