Your Health - Seasonal Affective Disorder

Seasonal Affective Disorder

(SAD)

Definition

Seasonal affective disorder (SAD) is a type of depression that corresponds to seasonal changes in light. It most commonly occurs in late fall and lasts through the winter and into spring. It's not uncommon to feel "down" during the winter months. But people with SAD are not able to function normally during these months. It often begins during adolescence or young adulthood.

Brain—Psychological Organ

SAD may be caused by fluctuations in hormones and brain chemicals.

Causes

The cause of SAD is not completely understood. It is clearly related to changes in seasonal light. Light affects cycles in the body. Lack of light during the winter months could possibly throw off levels of hormones and brain chemicals. This could contribute to the symptoms of SAD.

Scientists are also researching if SAD is related to lack of the chemical serotonin in the brain.

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition.

Sex: female
Living in northern latitudes

Symptoms

People with SAD have seasonal symptoms that come and go each year. They usually peak during the winter and disappear during the spring and summer.

Symptoms can include:

Depressed mood, feelings of sadness
Cravings for sweet or starchy foods
Overeating
Significant weight gain or loss
Lack of energy
Oversleeping or insomnia
Fatigue
Irritability
Social withdrawal
Difficulty concentrating
Decreased sexual desire

Diagnosis

The doctor will ask about your symptoms and medical history, and perform a physical exam. You may be referred to a specialist in treating depression.

A diagnosis of SAD will only be made if you have some of the symptoms above and:

Your symptoms have occurred annually for at least two years
You have complete relief from symptoms during the summer months

Treatment

Light Therapy

Light therapy is simple. The light box is made up of fluorescent bulbs, a reflective surface, and a diffusing screen. Ordinary household lighting is not sufficient. You sit a few feet away from the ultra-bright light for a certain amount of time each day, usually in the morning. You will be able to read or work during the therapy, as your eyes will remain open. Your doctor will probably start you off with 15-20 minutes a day. You will gradually increase the time, usually to 30-45 minutes daily.

There is some evidence that light therapy may be as effective as antidepressant therapy, but with fewer side effects.

Tanning beds are not recommended as a source of light therapy. They give off ultraviolet light, which can increase the risk of cancer. They also have not been proven effective for treating SAD. Many people find that getting outdoors for a walk each day is also helpful.

Anti-depressant Medications

Your doctor may prescribe anti-depressant medications. These medications are usually prescribed when a person does not feel better with light therapy or if the depression is very severe.

A medication called bupropion (Wellbutrin XL) has shown to be effective in preventing relapses of SAD.

Psychotherapy

Therapists can help you learn ways of managing stress and the symptoms of SAD.

Prevention

There are no guidelines for preventing SAD because the cause is not understood. Researchers are studying the role of light therapy in preventing SAD. Light therapy just before the winter months and before the onset of depressive symptoms may prevent SAD from developing.

RESOURCES:

Depression and Bipolar Support Alliance (DBSA)
http://www.dbsalliance.org/

National Mental Health Association
http://www.nmha.org/

CANADIAN RESOURCES:

Canadian Mental Health Center
http://www.cmha.ca/

Canadian Psychological Association
http://www.cpa.ca/

References:

American Academy of Family Physicians website. Available at: http://www.aafp.org/online/en/home.html .

Johansson C, Smedh C, Partonen T, et al. Seasonal affective disorder and serotonin-related polymorphisms. Neurobiology of Disease. 2001;8:351–357.

National Mental Health Association website. Available at: http://www.nmha.org/ .

Seasonal affective disorder. Mayo Clinic website. Available at: http://www.mayoclinic.com/health/seasonal-affective-disorder . Updated July 2008. Accessed February 23, 2009.

Society for Light Treatment and Biological Rhythms website. Available at: http://www.websciences.org/sltbr/ .

*7/20/06 DynaMed's Systematic Literature Surveillance http://www.epnet.com/dynamed/what.php : Lam RW, Levitt AJ, Levitan RD, et al. The Can-SAD study: a randomized controlled trial of the effectiveness of light therapy and fluoxetine in patients with winter seasonal affective disorder. Am J Psychiatry . 2006;163:805-812.

Last reviewed January 2009 by Theodor B. Rais, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.