Seasonal affective disorder: Treatment with light therapy
Seasonal affective disorder: Treatment with light therapy
Seasonal affective disorder — Explore light therapy as a treatment for this type of depression.
In the dark days of fall and winter, you may turn your face to the afternoon sun, seeking out what little light filters through fading gray skies. You may throw open the blinds, leave lights on throughout your home or even head south for a vacation — anything for a little more light. Or you may even be unable to crawl out of bed in the morning.
For people with a type of depression called seasonal affective disorder (SAD), this need for light takes on greater significance. Treatment with light therapy may offer a chance to regain the happier mood and brighter outlook that you lose to seasonal affective disorder. Learn how light therapy works and understand its pros and cons.
Understanding light therapy
In light therapy, you sit with your eyes open in front of a light box — a small, portable device that contains fluorescent bulbs or tubes. The light box emits a type and intensity of light that isn't found in normal household lighting, so simply sitting in front of a lamp in your living room won't relieve the symptoms of seasonal affective disorder. Light therapy mimics outdoor light and causes a biochemical change in your brain that lifts your mood, relieving symptoms of seasonal affective disorder.
Light therapy, also called bright light therapy or phototherapy, has been used to treat seasonal affective disorder since the early 1980s. Many mental health professionals now consider light therapy to be standard treatment for seasonal affective disorder.
However, light therapy hasn't been officially approved as a treatment by the Food and Drug Administration because of a lack of definitive evidence about its effectiveness in clinical trials. Results of some clinical trials have shown light therapy to be effective — and in some cases even more effective than antidepressants — while other research has shown that it's not effective. In addition, most studies have lasted less than six weeks.
You can purchase a light therapy box over-the-counter, which means you don't need a prescription. However, check with your doctor before trying light therapy to make sure it's appropriate for your situation.
Light therapy is often an effective treatment for seasonal affective disorder. You can sometimes engage in routine activities, such as reading, while undergoing light therapy.
The link between light and seasonal affective disorder
The precise cause of seasonal affective disorder isn't known, but genetics and your age may be factors. Most evidence, though, suggests that it arises from abnormalities in how your body manages its internal (circadian) biological rhythms or matches those rhythms to the 24-hour day. In particular, the hormone melatonin is thought to play a major role in seasonal affective disorder. Melatonin helps control body temperature, hormone secretion and sleep. It's produced in a specific area of your brain during the hours of darkness.
During the low-light months of fall and winter, people with seasonal affective disorder produce more melatonin than normal — enough to cause potentially debilitating symptoms of depression. But exposure to bright light, such as that from a light box, can suppress the brain's production of melatonin, helping regulate your body's internal clock and reducing symptoms.
The benefits of light therapy
Light therapy offers many potential benefits for people with seasonal affective disorder. It may be helpful for you if:
Treating other disorders
Drawbacks and side effects of light therapy
Light therapy isn't for everyone, nor is it always completely effective in reducing all of your symptoms.
You may be able to manage these problems by reducing treatment time, moving farther from the light box, taking breaks during long sessions or changing the time of day you use light therapy. Talk to your doctor for additional help and advice.
Who shouldn't use light therapy
How to use light therapy
Although you can buy light therapy boxes over-the-counter, it's important to consult your doctor when you use one. Done improperly, light therapy won't be effective, and it could even be harmful.
Averting your eyes
Three key elements
What to expect from light therapy
The general recommendation for most people with seasonal affective disorder is to begin treatment with light therapy in the early fall, as soon as the earliest symptoms start. Be on the alert for such symptoms as difficulty waking, daytime sleepiness and carbohydrate cravings. Treatment generally continues until spring, when outdoor light alone is sufficient to sustain a good mood and higher energy.
Some people experience seasonal affective disorder in the summer. And others who typically have winter depression may notice symptoms during prolonged periods of cloudy or rainy weather during other seasons. You and your doctor can adjust your light box treatment based on the timing and duration of your symptoms.
Sticking with it
With appropriate light therapy, you may start to feel better within several days. In some cases, though, it can take two or more weeks. Sticking to a consistent daily routine of light therapy sessions can help ensure that you maintain those benefits over time. If you interrupt light therapy during the winter months or stop too soon in the spring when you think you're improving, your symptoms could return.
Last Updated: 10/04/2006
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