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What Is SAD?

Seasonal Affective Disorder Is Common, But Very Treatable


Updated November 07, 2013


Winter can be beautiful, but even though a winter's day can seem bright, there often isn't enough sunlight to positively affect our mood.

Photo © ezagury

What Is SAD?

Seasonal affective disorder (SAD), is a type of depression that occurs during the winter months. Milder forms of SAD might be called the "winter blues."

People with inflammatory bowel disease (IBD) may already be more susceptible to depression. Therefore, it is important for anyone with IBD to keep on top of their mental health and to seek treatment for any symptoms of depression or SAD.

SAD symptoms begin in the late fall when there is less daylight (or, as we sometimes say, the days get shorter). Without treatment, symptoms of SAD may not begin to abate until late winter or early spring.

Who Gets SAD?

An estimated 10% to 20% of Americans may experience some form of SAD or winter blues. Women account for 70% to 80% of all people with SAD. SAD is more prevalent in the higher latitudes than it is in the lower latitudes where there is more sunlight. Some people who work in offices with little access to natural light may experience SAD all year long.

What Causes SAD?

One theory is that people with SAD have an imbalance in serotonin levels. Serotonin is an important chemical in the brain known as a neurotransmitter. A neurotransmitter is a molecule in the brain that helps nerve cells to work together. One of the roles serotonin has in the brain is to act as a traffic cop to other neurotransmitters. Without enough available serotonin, a range of body functions is affected, including mood.

When light passes through the eyes into the brain, serotonin is released. During the fall and winter, there is less daylight than in the spring and summer, which causes a drop in the body's serotonin levels.

Less daylight is a trigger for the body to increase production of another hormone -- melatonin. Melatonin is thought to help in the sleep process. The body naturally releases it both at night when there is less daylight and during sleep. Exposure to bright light at night can inhibit the release of melatonin.

Together, the lack of serotonin (which helps nerve cells cooperate) and the increase in melatonin (which puts a body to sleep) can trigger symptoms of SAD.

What Are The Symptoms of SAD?


  • Carbohydrate/sugar cravings (sometimes accompanied by weight gain)
  • Decreased sex drive
  • Difficulty in concentrating
  • Diminished productivity
  • Difficulty waking in the morning
  • Fatigue
  • Feeling depressed or sad
  • Irritability
  • Lethargy
  • Low body temperature
  • Sleeping too much
  • Withdrawal from social activities


How Is SAD Diagnosed?

Symptoms are the primary basis for the diagnosis of SAD. SAD is not the same as clinical depression because depression does not have a seasonal fluctuation.

What Is the Treatment for SAD?

Light Therapy. The basic treatment for SAD is light therapy. Both the American Medical Association and the American Psychiatric Association recommend light therapy. Light therapy is as simple as it sounds -- adding more light to the environment.

Light therapy can be started in late August or early September, before any symptoms of SAD start. Normally, light therapy is done each day upon waking in the morning. Some people may find that another session in the afternoon is helpful.

A device called a light box is often used for light therapy. The box contains fluorescent light bulbs, and is set up in a place that is convenient to receive treatment. This could be a nightstand, a desk, or the kitchen table. The light should not be looked at directly. Sessions with light therapy are generally about 30 minutes a day. Treatment should be individualized so that neither too much, nor not enough light is received.

Side effects from light therapy are possible, but are generally reported as minimal. Side effects can include:

  • Difficulty in sleeping
  • Eye strain
  • Feeling "wired"
  • Headaches
  • Irritability
  • Nausea

Antidepressants. Antidepressants are also used as a treatment for SAD. Selective serotonin reuptake inhibitors (SSRIs), like Zoloft (sertraline HCl), Prozac (fluoxetine), Paxil (paroxetine), or others may be used to treat symptoms in conjunction with light therapy.

Other Self-Treatment Ideas

  • Eat fewer carbohydrates.
  • Effectively manage stress.
  • Get more exercise.
  • Increase the amount of light in your daily environment, by adding lamps or skylights and trimming trees or bushes that block sunlight.
  • Maintain a consistent sleep schedule.
  • Sit near a window whenever possible.
  • Take walks on sunny days, even during winter.
  • Take a vacation in a sunny, warm location, if you are able.



Jacobs D. "An APA expert answers common questions about Seasonal Affective Disorder (SAD)." American Psychiatric Association. 31 Dec 07.

FamilyDoctor.org. "Seasonal Affective Disorder." American Academy of Family Physicians Sept 05. 31 Dec 07.

Lurie SJ, Gawinski B, Pierce D, ROUSSEAU SJ. "Seasonal Affective Disorder." American Family Physician 01 Nov 2006. 31 Dec 07.

Amber J. Tresca
About.com Inflammatory Bowel Disease (IBD)

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