If you tend to get more depressed, lethargic, or unfocused during late fall or winter, you might have a form of depression called Seasonal Affective Disorder.

Introduction

As summer comes to an end, most people feel a tinge of melancholy -- no more sunny afternoons and warm evenings. With the seasons changing there are less hours of daylight -- we wake up to darkness and leave work in darkness -- which means less time for pleasurable outdoor activities and more time stuck indoors. Together with the cold weather that discourages us from leaving our homes in the dead of winter, it stands to reason that most people experience some degree of "cabin fever" (edgy restlessness) and a desire to sleep more than usual.

Such reactions to seasonal shifts are natural. But for some people, winter's arrival brings on a more serious condition, one that can disrupt their lives and keep them from functioning normally at home and at work. Their symptoms go well beyond the typical "winter blahs."

What is Seasonal Affective Disorder?

Individuals who suffer from Seasonal Affective Disorder (SAD) suddenly develop bouts of crying, cravings for sweet and starchy foods, headaches, sleep impairment, and fatigue.

SAD has been found to affect varying numbers of people in different regions of the world. Some studies claim that anywhere from 0.9% of the population in Asia, up to 3% in Europe and 9.7% in North America are affected.

However, more conservative estimates, using very strict definitions of the disorder, suggest that approximately 1% of the people in the United States and 2-3% in Canada have SAD. This illness appears to be more prevalent the further north or south one goes from the equator. It usually begins during adolescence or young adulthood and affects women more than men; in fact, 75% of people with SAD are women ¹ . After the age of 55 the prevalence declines dramatically, such that the prevalence of SAD over 65 is very low.

SAD is a cyclic condition, in that symptoms only occur during late fall and winter. The causes of this depressive disorder are not well understood. Most probably heredity and an individual's chemical makeup are partially responsible.

It is thought that diminished sunlight triggers the symptoms. The reduced light probably disrupts biological, or circadian, rhythms. These rhythms, which constitute the body's internal "dark-light cycle clock", govern the timing of hormone production. When dark-light patterns are disrupted, melatonin, the hormone that promotes sleep, is produced in excessive amounts. This accounts for both SAD and jet lag.

Researchers also believe that the neuro-transmitter serotonin may play a role in the onset of SAD. This chemical, which influences depression, has been found to occur in varying levels according to the seasons, with lower levels observed in winter and spring and higher levels in the summer and fall. It is also believed that a person's genes may predispose him or her to this kind of seasonal variation in the production of serotonin ¹ .

If you have had a down mood and four of the following symptoms through at least two consecutive winters, you may have SAD:

• Loss of energy
• Anxiety
• Irritability
• Increased desire for sleep, including daytime sleepiness
• Headaches
• Episodes of crying
• Loss of interest in your usual activities, including sex
• Overeating, especially foods high in carbohydrates
• Difficulty concentrating
• Weight gain
• Social withdrawal

If there are no other reasons for you to feel depressed, such as disturbing or painful life events or another medical or psychiatric condition, it's a good idea to discuss this with your primary care physician or a mental health professional with experience in this area.

Treatments for SAD

Each person with SAD should be treated on an individual basis, in consultation with his or her health care professional. Treatment consists of selecting from the following methods, which have been found to be effective ¹ :

Light Therapy - To reset the body's internal clock, patients are given regular doses of full-spectrum light from late autumn to early spring. The "white" light matches the kind of light a person would get from natural sunlight shortly after sunrise or before sunset. However, this form of light therapy does not contain any harmful ultraviolet wavelengths. Light therapy is believed to be helpful because the extra light probably suppresses the overproduction of melatonin.

Most people prefer treatment to take place in their home, using a special light box designed for the purpose. The box uses a special bulb, not the kind used to light our homes. The individual sits about 18 inches from the box, facing it. It's not necessary to look directly at the box, but some experts advise briefly looking at it at regular intervals while eating, reading, talking on the phone, and so on.

The length of time for each treatment depends on the brightness of the bulb. For example, a less intense bulb may require 2 hours per session; a brighter bulb requires 25 to 45 minutes. It's best to conduct these sessions in the early morning or at dusk. One session a day is usually sufficient.

Light therapy should not be used if a person has skin- or eye-sensitivity. Also, people diagnosed with bipolar disorder (manic depressive disorder) or have pronounced periods of excess energy should avoid light therapy.

Check with your doctor before starting light therapy if you have an eye disorder such as glaucoma, cataracts or retinal detachment. Likewise, if you have depression that lasts throughout the entire year, you may be in need of treatment for the more common type of depression, rather than this seasonal variety -- which is linked to changes in light.

Medication - Medications used to treat clinical depression (i.e. anti-depressants) can be helpful to those diagnosed with SAD. Individuals should consult their physician about which medication is best suited for their needs. Please also consult your physician regarding the safety of taking non-prescription medicines such as St. John's Wort.

Psychotherapy - Although psychotherapy can be helpful in addition to light therapy or medications, it probably should not be the main treatment method for those suffering from SAD. However, as a supplement to medication and light therapy, it can help individuals better cope with their situation.

Exercise - Together with one or more of the above-mentioned treatments, people with SAD should remember to walk outdoors on sunny days during the winter. In general, exercising regularly helps to reduce stress, and those with SAD may find it particularly beneficial.

Other ways to get more light - If finances allow, a winter trip to a sunny location can be of help. Also, it is a good idea to increase the amount of light in one's home by adding windows or removing trees that block the sun.

Summary

People with Seasonal Affective Disorder usually feel fine in the spring and summer, then experience depressive symptoms in the fall and winter, when the decrease in daylight causes an increase in their biological production of a sleep hormone. Though they tend to sleep longer, they continue to feel lethargic and drowsy during the day. They also feel down, irritable, tearful, hungry, and unfocused.

Fortunately, effective treatments exist to eliminate the symptoms of SAD. With light therapy, medications and psychotherapy, no one has to endure the winter with this type of depression. With medical help, SAD sufferers can regain their energy and good spirits - and beat the winter blues.

Links

• National Mental Health Association Fact Sheet on SAD
• Canadian Consensus Guidelines for the Treatment of Seasonal Affective Disorder
• Walk Away From Depression?
• Menopause and Depression: Myth versus Reality

Winter Blues by Norman E. Rosenthal If You Think You Have Seasonal Affective Disorder by Clifford Taylor

Footnotes

1.

Canadian Consensus Guidelines for the Treatment of Seasonal Affective Disorder. RW. Lam, AJ. Levitt, Clinical and Academic Publishing: Canada, 2000