While fall brings crisp, cool air and changing leaves, it also means a dip in the length of sunlight we see each day.
As the daylight shortens, around 5 percent of U.S. adults begin to experience Seasonal Affective Disorder, or SAD, a recurrent form of depression that emerges in the winter.
The feelings of fatigue, sadness, loss of appetite and other symptoms of SAD are all tied to the body’s ability to sense and cope with the annual reduction of sunlight, said Dr. Paul Desan, the director of the Winter Depression Research Clinic at the Yale School of Medicine.
“There are connections between light-detecting, brightness-detecting cells in the eye and parts of the brain that control the body’s clock and also parts of the brain that control our emotions and our hormones,” Desan said. Melatonin, a sleep-related hormone, has also been linked to SAD. The body produces more melatonin when it’s dark.
Rates of SAD increase the farther one is from the equator, as daily sunlight hours shrink. Women are also more susceptible to the disorder. But, Desan notes, the disorder is highly treatable using light therapy and other treatments.
Here’s what to know about treating SAD.
The power of light
Light therapy, a daily environmental manipulation, is the standard method of treatment for Seasonal Affective Disorder. Medical professionals like Desan direct patients to use lightbox devices, like those listed on the Winter Depression Clinic’s website, for 30 minutes a day in the early morning.
”The research best supports a half an hour of 10,000 lux of light seven days a week before 8 a.m.,” he said. Lux is a measurement of light brightness, and 10,000 lux is about the brightness of being outside in July.
In light therapy, a lightbox is placed within a few feet of a patient in their field of view so the white, ultraviolet-free light strikes the eyes’ retinas. Ideally, placement would be convenient, like on a kitchen countertop or a desk, so the light therapy can work as you are also doing other things.
It’s all about working the therapy into a daily routine with minimal effort, Desan said. “If you have a small device that you have to be close to and can’t move at all, that’s not a practical therapy that’s comfortable for 30 minutes.”
Patients should avoid staring directly into the lightboxes as this can cause headaches and other issues, and some people benefit from easing into the routine with shorter initial sessions of light therapy.
Others, Desan said, may find it effective to expose themselves to lower levels of brightness for longer periods of time during the day. “For example, on the job, they may have a very brightly lit office, or a light next to their workstation.”
But light therapy can be dangerous for patients with retinal diseases and, like many medications, it can have adverse side effects, particularly for individuals with bipolar disorder, who may enter an overactivated hypomanic or manic state. Anyone interested in starting light therapy should only do so under the supervision of a medical professional.
Medication can help, but vitamin D supplements may not
While light therapy is the main treatment for Seasonal Affective Disorder, some patients can benefit from anti-depression medications. Wellbutrin, which uses bupropion as an active ingredient, is the only FDA-approved medication for preventing SAD. Practitioners are advised to have patients start the medication before winter begins, Desan said.
Other antidepressant medications can also be effective for treating SAD and should also begin under the advice and monitoring of a medical professional, Desan said.
While vitamin D production in the body is tied to sunlight exposure, Desan said. Vitamin D supplements have yet to show any effect in treating patients suffering from Seasonal Affective Disorder. The largest placebo-controlled trial specifically testing vitamin D as treatment for people who had SAD symptoms found no significant therapeutic effect, he said.
Behavior changes can lessen symptoms, too
Behavior changes are also part of treatment plans for Seasonal Affective Disorder as well as other forms of depression, including Subsyndromal SAD, which manifests as mood changes that do not fully meet the criteria for SAD.
There are “10 to 15% of people who have a symptom during the winter that they want help with. They just don’t feel as vigorous during the winter. Their energy is worse there. Their mood isn’t quite as good,” Desan said.
Exercise and maintaining regular activities, especially those that involve going outside, can help lessen symptoms. And for those who can afford it, traveling to a destination with longer periods of sunlight can help, Desan said.
Cognitive behavioral therapy also shows promise.
“In depression, people form beliefs that are negative about themselves, about their activities and so forth,” Desan said. “The therapist challenges those beliefs, and the therapist also encourages behaviors that are healthy, getting out and doing things as opposed to giving in to poor energy and withdrawing from the things that really are going to sustain you and make you feel better.”
