January 19, 2009 | Modern Hygienist
Life: Web Exclusive

Combat seasonal depression

Practical advice on how to recognize and respond.

by Nancy Stebbins, MD

Photo: Rosanne Olson/Getty Images

Craving sunlight? Feeling “down on your lux,” now that the days are shorter? If so, you’re not alone. Seasonal Affective Disorder, commonly known by its acronym, “SAD,” is a type of depression that strikes many people in the fall and winter. The good news? Once recognized, it is highly treatable, and often without medication.

What is SAD? The American Psychiatric Association, in its diagnostic manual (DSM IV) describes it as a major depressive disorder that recurs in a seasonal pattern. For most people, onset occurs in the fall, and worsens as the days continue to grow shorter.  Symptoms abate in spring and are absent in summer. The reverse pattern is seen on rare occasions, with lows in the summer. Occasionally, people with winter lows will also have summer highs or manias, and meet the criteria for bipolar disorder.

Depression can affect sleep, appetite, and energy in either direction (up or down), but a consistent pattern is seen with SAD: usually appetite is increased, especially for carbohydrates (carbohydrate craving) and weight gain is common. Energy is decreased, and the person needs more sleep than usual. A person with SAD may experience mood as sad, apathetic, or a lowered sense of general well-being.

Although SAD refers to a major depressive episode, mood related depression occurs along a spectrum of severity. Some people have only mild symptoms (“winter blues”) and others have serious depression and may even become suicidal.

Risk factors and treatment

Who is at risk for SAD? The answer takes into account both genetic and geographical factors. Regarding geography, SAD is seen more frequently in areas with shorter days and less sunlight in winter. According to the Cleveland Clinic, 10% of Alaskan residents suffer from SAD, as compared to 1% of residents of Florida.¹

Regarding genetics, SAD seems to run in families, and vulnerability to limited light varies greatly from person to person. Some people are so sensitive that overcast days will lower their mood any time of year.

So how is SAD treated? The mainstay of treatment is light therapy—replacing sunlight using commercially available light boxes. Most commonly used are fluorescent light boxes which use a diffusing screen to filter out ultraviolet light, in order to avoid skin and eye damage. (Other types of available light therapy use “blue wave” light or dawn simulators.) The light box should produce 10,000 lux; a lux is a measure of light intensity. For the sake of comparison, direct sunlight is about 100,000 lux, a sunny day about 10,000 to 20,000 lux, an overcast day about 1000 lux, and typical indoor lighting about 200 lux.

Light boxes can be purchased without a prescription. However, it is always a good idea to discuss symptoms and treatment of depression with one’s physician. Additionally, some insurers will cover the cost, if the light boxes are prescribed.

Light boxes normally rest on a table top. The person faces the light at a close distance, and with eyes open. Many people use this time to have breakfast or read. Although some people have tried using other types of full-spectrum lights, such as plant lights or aquarium lights, the intensity of these is much lower and there is no evidence that they treat SAD. Tanning beds are also not a good substitute, due to ultraviolet light exposure.

Time of light exposure sessions is important. Most people have best results with early morning exposure, ranging from 30 to 90 minutes per day. Evening light is more likely to cause agitation or insomnia. One very rare complication was portrayed on the TV show Northern Exposure: a patient was prescribed light therapy for SAD, and developed euphoria and agitation. Unfortunately, his light device was wearable, and the problem was getting it away from him. This serves as a reminder that most treatments for depression, including light exposure, can bring out a manic episode in someone with bipolar disorder.

There are few side other effects of light therapy. Most commonly described are headaches and eyestrain. People with ocular disorders are advised to check with their eye doctor prior to use.

If light therapy is not practical for an individual, or is ineffective, antidepressants can be used. For recurrent seasonal depression, they can be prescribed in the fall a few weeks before symptoms are predicted, and tapered in the spring.

If you believe that you or someone you know suffers from SAD, please discuss your symptoms with your physician. For more information, an excellent reference is Winter Blues, Revised Edition: Everything You Need To Know To Beat Seasonal Affective Disorder, by Norman E. Rosenthal. 

References

1. Cleveland Clinic: “What is Seasonal Depression?” Link.

General resources: Overview of SAD, including light box buying guide. Link. 

Winter Blues, Revised Edition: Everything You Need To Know To Beat Seasonal Affective Disorder, by Norman E. Rosenthal. The Guilford Press; Revised edition (September 16, 2006)