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Seasonal Affective Disorder: More than Just the “Winter Blues”

As the temperature drops and the days get shorter, it feels like all everyone is talking about is holiday cheer. Although winter brings celebrations, gifts, and twinkling lights, it also comes with the dreaded winter blues. You’re probably familiar with the feeling—It’s the shift in mood that happens on dark, cold days that leaves you feeling sad and tired. Most people experience the winter blues on occasion but, for some people, the winter blues linger and affect a person’s ability to complete everyday tasks. When this happens, it may be a clinical condition known as seasonal affective disorder (SAD).

“Winter Blues” vs SAD

So how do you tell the difference between the winter blues and seasonal affective disorder? The answer lies in the severity and duration of symptoms. The winter blues is not a clinical diagnosis—it is a temporary feeling. Symptoms include trouble sleeping, fatigue, and feelings of sadness that do not interfere with daily functioning and can be managed with lifestyle changes.1

According to the American Psychiatric Association, “SAD is more than just “winter blues.” The symptoms can be distressing and overwhelming and can interfere with daily functioning.” It is categorized in the Diagnostic Manual of Mental Disorders (DSM-5) as a Major Depressive Disorder with a Seasonal Pattern.2

About 5 percent of adults in the U.S. experience SAD and it typically lasts about 40 percent of the year.2 In most cases, seasonal affective disorder symptoms appear in the late fall or early winter and go away in the spring and summer months as the days get sunnier. However, a small percentage of individuals with SAD experience the opposite pattern and have symptoms that begin in the spring and persist through the end of summer.3

Signs and Symptoms

Since seasonal affective disorder is a depressive disorder, the signs and symptoms you should keep an eye out for are similar to those associated with major depression. The National Institute of Mental Health (NIMH) lists the symptoms of major depression as:

  • Feeling depressed most of the day, nearly every day

  • Losing interest in activities you once enjoyed

  • Experiencing changes in appetite or weight

  • Having problems with sleep

  • Feeling sluggish or agitated

  • Having low energy

  • Feeling hopeless or worthless

  • Having difficulty concentrating

  • Having frequent thoughts of death or suicide

For winter-pattern SAD, additional specific symptoms may include:

  • Oversleeping (hypersomnia)

  • Overeating, particularly with a craving for carbohydrates

  • Weight gain

  • Social withdrawal (feeling like “hibernating”)

Specific symptoms for summer-pattern SAD may include:

  • Trouble sleeping (insomnia)

  • Poor appetite, leading to weight loss

  • Restlessness and agitation

  • Anxiety

  • Episodes of violent behavior

It’s important to note that not every person with SAD will experience all the symptoms listed above.4

Getting a Diagnosis

If you think you may be suffering from SAD, talk to your health care provider or a mental health specialist. They will likely ask you about your symptoms to determine if you meet the criteria for SAD.

According to the NIMH, to be diagnosed with SAD, a person must meet the following criteria:

  • They must have symptoms of major depression or the more specific symptoms listed above.

  • The depressive episodes must occur during specific seasons (i.e., only during the winter months or the summer months) for at least 2 consecutive years. However, not all people with SAD experience symptoms every year.

  • The episodes must be much more frequent than other depressive episodes that the person may have had at other times of the year during their lifetime.4

It is best to seek help right away if you are experiencing symptoms of SAD or major depression. A health care professional can provide a clinical diagnosis and recommend ways to manage and treat mental health disorders.

What Causes SAD?

Anyone can be affected by seasonal affective disorder. The American Psychiatric Association states, “SAD has been linked to a biochemical imbalance in the brain prompted by shorter daylight hours and less sunlight in winter. As seasons change, people experience a shift in their biological internal clock or circadian rhythm that can cause them to be out of step with their daily schedule.”2 Individuals with SAD have lower levels of serotonin and vitamin D and higher levels of melatonin than the average person, resulting in changes in sleep, mood, and behavior.3

Some groups of people may be at an increased risk of developing seasonal affective disorder. Because of its connection to light expose, SAD is more common in people living far from the equator where there are fewer daylight hours in the winter.2 SAD is also four times more common in women than in men and the age of onset for SAD is typically between the ages of 18 and 30. Often, instances of SAD decrease as an individual ages.3

Additionally, SAD is more common in people with a major depressive disorder or bipolar disorder, especially bipolar II disorder. Frequently, people with SAD tend to have other mental disorders, such as attention-deficit/hyperactivity disorder (ADHD), an eating disorder, an anxiety disorder, or a panic disorder. Sometimes SAD runs in families and is more common in people who have relatives with major depression or schizophrenia.4

Treatment for SAD

There are four categories of treatment for SAD that can be used alone or in combination.

  • Light Therapy: Light therapy has been used for treating SAD since the 1980’s. The goal is to expose people to a bright light every day to mimic natural sunshine. A person will sit in front of a light box (about 20 times brighter than an ordinary indoor light) each morning for 30-45 minutes.

  • Cognitive Behavioral Therapy: Cognitive behavioral therapy (CBT) is also known as psychotherapy or “talk therapy.” During CBT, discussions primarily focus on replacing negative thoughts with positive thoughts and scheduling engaging activities to combat the loss of interest many people with SAD often experience.

  • Medications: Sometimes anti-depressants are prescribed to treat the chemical imbalances that cause SAD.

  • Vitamin D: Some studies suggest that vitamin D supplements may help improve symptoms of SAD.

People with a history of SAD may benefit from starting the treatments above to prevent the onset or severity of symptoms.4


If you or someone you know is in immediate distress or is thinking about hurting themselves, call the National Suicide Prevention Lifeline toll-free at 1-800-273-TALK (8255). You also can text the Crisis Text Line (HELLO to 741741) or use the Lifeline Chat on the National Suicide Prevention Lifeline website.



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