Accurate diagnosis, proper treatment essential for SAD

Although winter depression was described by the authors of classical antiquity, it was officially designated as a disease only about 20 years ago. We see lots of evidence of people suffering from SAD in our practice. The incidence is related to latitude.

Studies estimate that about 5 percent of people who live in areas at about the same latitude as Connecticut suffer from true SAD; about three times that number report significant problems with mood, energy and sleep during the winter months. SAD is almost nonexistent in sunny climates such as Florida, but farther north, in Maine, for example, we might expect the incidence to be about 10 percent.

SAD affects women in greater numbers
Three times as many women suffer from SAD as men do. Women suffer from depression of all kinds more frequently than men, and women with premenstrual syndrome are much more likely to be afflicted with SAD. Winter depression usually begins in early adulthood, but it has been reported in young children as well.

Evolution of treatment
From the beginning, clinicians tried to treat the disease with light. The early treatment protocols called for very long treatment periods in the morning and evening. Clinicians now prefer light approaching the intensity an individual might naturally be exposed to outside on a sunny day. It wasn’t until 1997 that we had well-designed clinical trials suggesting that morning therapy was most effective. This new study, which has aroused lots of interest, refines that theory even more, suggesting 80 percent cure rates for individuals treated in the early morning, roughly 8.5 hours after their bodies begin producing melatonin the evening before.

Everyone has their own biological clock, and we can guess what someone’s clock is roughly by monitoring what time people get up and when they go to sleep. Measuring the onset of melatonin production is a more accurate measure. If your melatonin production begins at 10 p.m., we’d say your clock was running rather late compared to someone whose melatonin began around 6 p.m. The researchers in this study showed that light therapy resets this biological clock. And if you give the right kind of light at the right time for the right duration, you may be able to effectively treat winter depression for 80 percent of patients.

Professional diagnosis important
I frequently get calls from people who think they might have winter depression. It is not uncommon to misdiagnose depression, so my advice is always the same: consult with a mental health professional to determine if you have depression, and if so, what kind. Treatment for SAD is specific to that disease, so a professional diagnosis is important.

In addition, there is a lot of merchandise available online marketed as light therapy that is totally ineffective, such as light boxes that fail to emit the right kind or correct intensity of light, glasses with different colored lenses, full-spectrum light bulbs and poorly designed dawn simulators. Consulting with a professional will make it possible to obtain a medical grade light device that provides the right amount and kind of light. Medical grade light boxes also do not emit ultraviolet light, which is an important safety consideration. Many insurance plans will cover the cost of the device if it is properly prescribed by a clinician.

Current focus
Now that research has demonstrated that early morning light exposure is the most effective, the focus is on finding ways to make the therapy more convenient for people. Patients are typically required to sit by a lighting device for 30 to 45 minutes each morning, which can be difficult for people with busy lifestyles. A variety of experimental devices are being tested that are smaller and more mobile to make treatment as user-friendly as possible.

Often patients are able to read a newspaper or watch television while getting their light exposure. It’s important to sit facing the light since eye exposure is critical. Because of the exposure of eyes to the light, it is important for individuals who have retinal disease to check with their ophthalmologist before treatment since bright light may worsen some kinds of retinal disease. It’s also a good idea for anyone over 65 to check with an eye doctor to ensure they do not have an undiagnosed retinal condition.

Negative side effects are rare. Individuals with bipolar disorder may experience elevated mood swings after light exposure just as they might with antidepressant medications.

Other treatment options
Some people with SAD are helped by antidepressants; others do best with the light therapy, which is another reason why professional consultation is essential if you suspect you may have depression of any kind.

More research
Research continues in a search for more convenient light devices and to determine more precisely what kind of light is likely to have the most beneficial effect on circadian rhythms. In addition, researchers are trying to determine if treatment with negative ions in the air, which are present at higher levels in spring, might help those suffering from winter depression. Organisms of all kinds, including human beings, are sensitive to all kinds of environmental signals, and perhaps our bodies respond to the change in the atmospheric ionization that occurs with the seasons.

The Winter Depression Research Center at Yale is very interested in investigating the effects of exposure to negative ions. The research on the therapeutic effect of negative ion generators is preliminary but already negative ion-generating devices are appearing for sale on the Internet. It should be emphasized that it is not clear whether these devices have any therapeutic value.

Researchers are also studying the role of bilirubin as a light receptor. Research has shown that low levels of bilirubin circulating in the body at night may be associated with SAD. We continue to search for more clues that could lead to effective treatment.

The Terman study offers retrospective data indicating that synchronizing light treatment and circadian rhythms is effective in relieving the symptoms of people suffering from SAD. We will need additional prospective studies to determine if the effectiveness of this treatment approach can be duplicated.

Dr. Paul Desan directs the Yale Psychiatric Consultation Service. He is an attending psychiatrist at the Yale-New Haven Psychiatric Hospital and an assistant professor of psychiatry at the Yale University School of Medicine.