Winter Blues vs. Seasonal Affective Disorder

Sad man depressed in his room

Vasily Pindyurin / Getty Images

During the winter months, the sunrise is later and the sunset is earlier, which forces many people to commute to and from work in the dark after working in an office all day. Some people may go multiple days in a row before stepping outside into the sunshine.

Living in the dark can affect everyone; even if you are a happy-go-lucky person without any past history of depression. Our vitamin D stores can be depleted in the winter and our inside time usually far outweighs our outside time.

A shift in mood is not necessarily alarming unless it permeates multiple aspects of your life. 

So how do we differentiate seasonal affective disorder (SAD), also commonly referred to as season depression, from the winter blues and what can we do to boost our mood during the cold-weather months?

What Is the Winter Blues?

Winter Blues

The winter blues is a mental state comprised of feelings of sadness and fatigue during the coldest and darkest months of the year.

It may be hard to get out of bed some mornings, you may have trouble sleeping and you may feel unmotivated to complete daily tasks or to get outside. However, the winter blues is temporary and does not affect your ability to function throughout the day.

You may feel down and out, but you are still completing your necessary daily tasks, such as going to work and completing household duties. Winter blues is to sadness as seasonal affective disorder is to depression.

Symptoms of the Winter Blues

  • Feelings of sadness during the winter months
  • Lack of motivation to complete some tasks but can handle major requirements such as going to work and taking care of the house
  • Trouble sleeping
  • Spending one or two days in bed  

Although winter blues is not considered a mental health disorder and does not interfere with our daily functions, it can still make us feel “down and out."

Treatment For the Winter Blues

Lifestyle changes and self-care routines are key to improving your mood in the winter months.

Seek Out the Sun

The sun is an unlimited source of vitamin D which is essential for circadian rhythm regulation and as a result can increase our energy levels and boost our mood. If you live in a location that snows and rains during the winter, consider traveling to a sunny tropical place in the winter to reset your clock and soak up the warm rays.

Adopt a Regular Sleep/Wake Routine

Going to bed at the same time every night and waking up at the same time every morning can help stabilize your internal clock and allow you to wake up feeling refreshed and energized instead of feeling fatigued throughout the day.

Exercise Daily

Exercise releases endorphins, which are known to improve mood and energy. Exercising at least 30 minutes each day for five days a week can improve your energy levels and mood.

Exercising outdoors is even better as it allows you to breathe in the fresh air, soak up the sun and enjoy nature.

Eat a Balanced Diet

In the winter, many of us crave sweets and complex carbohydrates, which can leave us feeling tired. Try to incorporate whole grains and fresh produce into your diet on a daily basis.

Try eating foods that are rich in vitamin D such as fish, egg yolks, mushrooms and foods such as milk, juices and cereals that are fortified with vitamin D.

Consider Vitamin D Supplements

The recommended daily vitamin D intake is approximately 1,000 IU (25 mcg) per day. However, 40% of U.S. adults are deficient in vitamin D. Although it is best to obtain the daily dosage of vitamin D from diet and sunlight, taking daily vitamin D supplements may be the best way to improve your mood during the winter months.

Stay Connected With Friends

A healthy social support system is important to feel connected and to get you out of the house during the long winter months. Whether it is cooking, skiing, or a night out on the town, spending time with friends and loved ones can help boost your mood in addition to having someone to talk to about your feelings.

What Is Seasonal Affective Disorder?

Seasonal Affective Disorder

Seasonal affective disorder (SAD) also known as seasonal depression is a mental health disorder characterized by distressing and overwhelming feelings of sadness that can interfere with daily functioning.

The Diagnostic Manual of Mental Disorders (DSM-5) identifies SAD as a type of depression known as major depressive disorder (MDD) with a seasonal pattern.

SAD is more than the “winter blues” because symptoms of SAD can be severe and even debilitating. SAD differs from MDD in that MDD occurs throughout the year and does not depend on seasonal change.

SAD starts to become apparent in the fall, pique in the winter, and resolves in the springtime and is more apparent for individuals living in the Pacific Northwest and the Northeast where grey skies are prominent four to six months out of the year.

SAD Can Appear in the Summer Months

Seasonal affective disorder is most prevalent during the winter months and when we think of SAD, we think of cold, dark winter days; however, SAD also appears in the summer, but at a much more rare occurrence.

According to research, "A small share of people with SAD show the reverse pattern, being sensitive to summer's longer days. The very existence of opposite winter-summer patterns suggested to researchers that this mood disorder stems from a problem in adapting to the physical environment."

SAD Statistics

  • SAD is estimated to affect 10 million Americans
  • SAD is four times more common in women than in men
  • The age of onset for SAD is estimated to be between the age of 18 and 30 and rarely affects people younger than 20 years of age
  • The incidence of SAD decreases as the individual ages
  • Six percent of individuals with SAD require hospitalization

Symptoms of SAD

  • Overeating
  • Craving foods that contain complex carbohydrates
  • Weight gain
  • Difficulty sleeping
  • Depressed mood most of the day, nearly every day
  • Loss of interest in activities you typically enjoy
  • Withdrawal and isolation from loved ones
  • Inability to focus and concentrate on work performance and household tasks
  • Lethargy and fatigue
  • Hopelessness
  • Suicidal thoughts

Note: To be diagnosed with SAD, your symptoms must interfere with your daily functioning.

Causes of SAD

Changes to our internal clocks and hormones fluctuation both contribute to SAD. The main causes of SAD are listed below.

Circadian Rhythm

Our body’s internal biological clock—circadian rhythm—drastically changes when winter approaches. The decrease in daily sunlight over a long period of signals to our body that it is nighttime which leads to fatigue throughout the day.


Serotonin is a chemical in the brain that plays a large role in mood regulation. Serotonin is also the primary ingredient in selective serotonin reuptake inhibitors (SSRIs), the first-line (i.e., primary) treatment for moderate to severe depression.

Individuals with seasonal affective disorder have lower levels of serotonin. Brain imaging studies such as MRIs and CTs have shown individuals with seasonal depression to have higher levels of serotonin transporter proteins. These transporter proteins, "transport" serotonin out of the brain, therefore lowering the levels of serotonin in these individuals with seasonal affective disorder.

Selective serotonin reuptake inhibitors (SSRIs), increase the level of serotonin in the brain by preventing its reuptake and destruction. As a result, SSRIs are used for individuals with seasonal affective disorder to help boost serotonin levels and improve mood.


Melatonin is a specific sleep hormone that is stored and released by the pineal gland in the brain. Melatonin is responsible for sleep patterns and plays a crucial role in circadian rhythm regulation and therefore highly affects mood.

Darkness stimulates the production of melatonin, preparing the body for sleep. As a result, melatonin is produced at higher levels when the days are shorter and darker, resulting in feelings of fatigue throughout the day.

Vitamin D

Vitamin D is produced in our body from both sunlight and our dietary intake. When sunlight is greatly reduced due to the decreased length of daytime in the winter, our body’s supply of vitamin D becomes depleted.

Vitamin D is believed to play a role in the regulation of serotonin. Therefore, insufficient levels of vitamin D can contribute to feelings of depression.

Treatment For SAD

“Once SAD was identified, researchers hypothesized that its typical appearance with winter had something to do with lowered exposure to sunlight. The obvious next step was to lengthen exposure to light intensity more akin to outdoor levels; it worked."


Antidepressants, particularly SSRIs, are the medication of choice in the treatment of SAD.

Examples include citalopram, fluoxetine, escitalopram, sertraline, and paroxetine. SSRIs take approximately four to six weeks to work, and some side effects may include decreased libido and weight gain.

The FDA has approved another antidepressant, known as bupropion, to treat SAD. Bupropion is a second-line medication (i.e., medication that is prescribed if the primary treatment is ineffective) and is used to treat those dealing with SAD who could not tolerate SSRIs.

Light Therapy

Light therapy, also known as phototherapy, is considered the first-line treatment for individuals with SAD.

A light therapy box mimics outdoor light by emitting as little UV light as possible. Researchers believe this type of light causes a chemical change in the brain that lifts your mood and eases other symptoms of SAD.

Light therapy and melatonin have been shown to improve signs and symptoms associated with SAD because they affect our circadian rhythms at different times of the day. For example, administering light therapy in the morning upon waking up and taking melatonin a few hours before bedtime has been shown to help regulate our circadian rhythm.

There are specific light boxes that are used to treat various conditions:

  • Light boxes to treat SAD filter out ultraviolet (UV) light
  • Light boxes that treat skin disorders use UV light (and could potentially damage your eyes if used incorrectly)

A special light box that gives off 10,000 lux of fluorescent light, more than 20 times brighter than most indoor light, increases serotonin in your brain, a neurotransmitter that is responsible for mood.

Light boxes for SAD can be purchased without a prescription and can be used in all indoor settings such as the home or office. Some light boxes resemble lamps while others resemble rectangular boxes.

They average cost for this kind of light box is $75, and bulbs should be replaced every two to three years. If you have SAD, remember to always keep your light box handy during the winter months.

Buying and Using a Light Box

If you're in the market for a light box to help lessen your symptoms of SAD, the light box you choose should provide an exposure of 10,000 lux of light and emit as little UV light as possible.

After purchasing a light box, keep the following recommendations in mind when you begin to use it:

  • Use it within the first hour of waking up in the morning for about 20 to 30 minutes
  • Keep the light box at a distance of about 16 to 24 inches (41 to 61 centimeters) from your face
  • You can keep your eyes open but do not look directly at the light

By following these tips, you should start to see an improvement in your symptoms within one to two weeks.

Dawn Simulators

Studies have shown that dawn simulators are equivalent to light box therapy for the treatment of SAD. Dawn simulators work as an alarm clock but replace the gradual intensity of a bedside light instead of giving off a loud, jarring beeping noise.

These devices gradually increase the strength of the light over 30 to 60 minutes during the early morning awakening process, simulating early morning dawn.

This gradual increase in light reaches the retina through your translucent eyelids, and by the time the individual is awake, the treatment has subsided.

Lifestyle Modifications

Making changes to your routine can be used to alleviate the symptoms of SAD and the winter blues.

But, when treating SAD, these lifestyle changes must be used in addition to other treatment options including light therapy and antidepressants. On the other hand, people who are experiencing winter blues can benefit from lifestyle modifications and self-care routines alone.

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  1. National Institutes of Health. Office of Dietary Supplements: Vitamin D Fact Sheet for Health Professionals. Updated October 9, 2020.

  2. American Psychological Association. Bright lights, big relief: treating seasonal affective disorder. Published June 26, 2006.