Seasonal Affective Disorder (SAD)

Seasonal Affective Disorder (SAD)

Seasonal affective disorder (SAD) is commonly referred to as winter depression in the northern hemisphere, but also occurs in the southern hemisphere during their winter. The essential diagnostic feature is a consistent pattern of depression occurring over at least the past 2 years during the winter months, with remission (no symptoms) during the summer. While depressive episodes may occur during the summer months, winter episodes far outnumber summer episodes. Some people even develop hypomanic or manic symptoms during the summer (increased activity, poor sleep, impulsive behavior, etc.).

Symptoms characteristic of SAD include fatigue, oversleeping, overeating with weight gain and craving for carbohydrates, avoidance of social situations, sensitivity to rejection, heavy feeling in the arms or legs, poor concentration, difficulty completing tasks, and irritability. Many patients begin to notice symptoms as the days shorten, with January and February typically the worse months. Symptoms begin to improve as days lengthen. The illness tends to begin when patients are in their early to mid twenties, with more women than men developing SAD (4:1).

Phototherapy: Earlier studies used 2500 lux for 2 - 3 hours. We now know that 10,000 lux for 30 - 90 minutes works just as well. Many people with SAD begin with 10 - 15 minute sessions, and gradually increase to average 30 - 45 minutes a day. Light therapy works best when used early in the morning, especially when it is still dark outside, but can be used twice daily. Additional light exposure during the afternoon may be helpful for patients who do not respond as well to morning-only use. The light source should be within 4 feet of the eyes. You should not look directly into the light, but your eyes must be open for light to be effective. There does not appear to be any differences in effectiveness among various wavelengths of light used. Tanning beds are ineffective and can be dangerous because of the UV light used. When used to treat depression, light therapy generally takes 2-4 days to become effective, with complete remission usually occurring within 2-4 weeks. Most people with SAD use light therapy daily during the winter.

• Most people use lights specifically designed for phototherapy, but some have found 4-lamp fluorescent light fixtures just as effective. Some have also found exposure to an hour of sunlight early in the morning (especially with a good walk) as effective as a light box.

• Too much light exposure may lead to irritability, inability to sleep, especially awakening too early in the morning, feeling "wired," headache, eyestrain, nausea, and overactivity, but rarely results in any significant problems. The most common side effect is eye irritation, which often responds to increasing the humidity in the house, or sitting farther away from the light. There has been no evidence of long-term damage to the eyes from light therapy.

• There are other treatments which can be effective for people with SAD who do not or only partially respond to light therapy. Please contact your physician if depressive symptoms appear or persist despite use of light.

Additional resources: Winter Blues by Norman Rosenthal (Guilford Press), Seasonal Affective Disorder, by Angela Smyth (Harper Collins Publishers).

OTHER SOURCES OF INFORMATION:

National Organization for Seasonal Affective Disorders (NOSAD)
P.O. Box 40190
Washington, D.C. 20016

National Depressive and Manic Depressive Association (NDMDA)
730 N. Franklin, Suite 501
Chicago, IL 60610
800-826-3632

Society for Light Treatment and Biological Rhythms
10200 W. 44^th Ave., Suite 304
Wheat Ridge, CO 80033-2840
(303) 424-3697

Seasonal Studies Program
National Institute of Mental Health
Building 10, Room 4S-239
9000 Rockville Pike
Bethesda, MD 20892
(301) 496-2141

SphereOne, Inc.
20 Easedale Rd.
Wayne, NJ 07470
(201) 942-9772

The following companies provide high intensity/full spectrum lights (addresses obtained off the internet):

Apollo Light Systems Inc.
352 West 1060 South
Orem, UT 84058
(800) 545-9667

Bio-Brite Inc.
7315 Wisconsin Ave., #1300W
Bethesda, MD 20814-3202
(800) 621-LITE

Duro-Test
9 Law Dr.
Fairfield, NJ 07007
(800) BUY-DURO

Enviro-Med
1600 Side effects, 141^st Ave.
Vancouver, WA 98684
(800) 222-DAWN

Environmental Lighting Concepts, Inc.
3923 Coconut Palm Dr., #101
Tampa, FL 33619
(800) 842-8848

Hughes Lighting Technologies
34 Yacht Club Dr.
Lake Hopatcong, NJ 07849
973-663-1214

Hydro/Aquatic Technologies
P.O. Box 777
Princess Anne, MD 21853

Northern Light Technologies
8971 Henri Bourassa West
Montreal, Canada H45 1P7
800-263-0066

OTT bioLIGHTSYSTEMS, Inc.
28 Parker Way
Santa Barbara, CA 93101
(800) 234-3724

The SunBox Co.
19217 Orbit Dr.
Gaithersburg, MD 20879
(800) LITE-YOU

Vitality Concepts, Inc.
(773) 275-1443

See related Patient Textbooks about Psychiatry.

See related Patient Topics Depression, Mental Health and Behavior, Psychiatry or Seasonal Affective Disorder.

See related Provider Textbooks about Psychiatry.

See related Provider Topics Depression, Mental Health and Behavior or Psychiatry.

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