Seasonal affective disorder

Although April has been deemed the cruelest month, February may be the SADdest. For many of us in the higher latitudes, seasonal affective disorder, which recurs in the fall and ends in the spring, has exacted its cumulative toll. Some. of its symptoms are typical of depression --sadness, irritability, inability to concentrate, withdrawal into solitude, and loss of interest in life. Other manifestations may include excessive and restless sleep, lethargy during waking hours, increased appetite, carbohydrate craving, and weight gains averaging 10 pounds.

Probable causes
Researchers have associated SAD with a diminished exposure to light and have established that more than 80% of patients with SAD are women, most of whom developed their first symptoms while in their 20s. Yet scientists haven't pinpointed the malady's precise mechanism. There are several speculations, most of which relate to melatonin, the hormone thought to play a major role in regulating the body's 24-hour cycle. Melatonin production takes place in the pineal gland, a pea-sized organ buffed deep in the brain, and in the photoreceptors of the retina. It is stimulated by darkness and suppressed by light, and thus is present in greater concentrations in the winter.

Many researchers believe that SAD sufferers are either extrasensitive to dim light and manufacture too much of the hormone or are oversensitive to the usual amount that is produced. Others maintain that people with SAD secrete melatonin later in the day than their unaffected counterparts, disrupting theft circadian rhythms. Because most women appear to "outgrow" SAD after menopause, some theorize that it may be related to female hormone levels.

There is also speculation that dopamine -- a neurotransmitter, or chemical that ferries signals between nerves and brain cells -- may play a role in SAD. Depletion of another neurotransmitter, serotonin, has been implicated in the carbohydrate craving that often accompanies SAD.

Treatment
Whatever SAD's biochemical roots, it can be alleviated with the one thing missing from the winter equation -- bright light. Regular exposure to bright light can alleviate the symptoms for up to 80% of people with SAD. The simplest solution may be to get to a sunnier clime. The incidence of SAD is almost 10% in New Hampshire, but only about 1% in Florida.

For those who can't engineer winter getaways, therapy using artificial light may do the trick. During light therapy the patient sits three feet away from a bank of fluorescent lights mounted on a metal reflector and shielded with a plastic screen. The intensity of light emitted is about 10,000 lux, which is about 20 times brighter than ordinary room light and is designed to approximate dawn. This treatment requires from 20 minutes to 2 hours of exposure daily and can be undertaken at home. However, it should be done only under the guidance of a qualified health professional.

Light boxes are classified as experimental devices by the U.S. Food and Drug Administration. Therefore, manufacturers are not allowed to market them for the treatment of SAD, and the many different products available are not regulated.

A light box costs anywhere from $300 to $500 -an expense that is covered by some, but not all, health plans. Some manufacturers will rent light boxes for a trial period to allow the user to determine whether or not the therapy is beneficial. Most of the devices are designed to sit on a table or desk; some are portable and lightweight.

Those who respond to light therapy may notice that their moods have improved as soon as 2 to 4 days into the course of treatment. The symptoms may disappear completely within a week or two.

A few people have reported side effects from treatment, including irritability, eye strain, headaches, or insomnia. Light therapy is not recommended for people who have photosensitive skin or are taking drugs that increase light sensitivity, or for those who have had eye surgery.

SAD can also be treated with antidepressant drugs. Since the standard tricyclics tend to cause drowsiness and increased appetite, the newer selective serotonin reuptake inhibitors (SSRIs), which often have the reverse effects, may be better Do you have a alternatives. Researchers question or subject are also investigating you would like us to address? Write to: whether a melatonin supplement given at just the Editor right time of day could reset the body's clock. For some patients a combination of drug treatment and light therapy may be most effective.

If you're interested in learning more about SAD or light therapy call the National Institutes of Mental Health at (301) 496-2141.

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