Light Therapy Can Battle Seasonal Affective Disorder (SAD)
What is Seasonal Affective Disorder?
Seasonal affective disorder (SAD), also known as winter depression, is a type of mood disorder that occurs during the winter months. Generally, people begin to experience symptoms during the late fall, continuing on through winter until spring. Symptoms include:
- loss of energy
- sleeping too much
- craving sweets and carbohydrates
- gaining weight
What Causes Seasonal Affective Disorder?
There are a few different theories as to what causes seasonal affective disorder. In the end, they all come back to one fundamental fact: not enough sunlight. According to one theory, disruptions in circadian rhythm, due to the loss of daylight, lead to depression. The circadian rhythm is like the body's internal clock that keeps track of day and night, when to sleep and when to wake up, etc. It regulates hormone levels. For some people, when there is insufficient light, the circadian rhythm gets thrown off, and hormone regulation goes amiss, causing depression. Another theory holds that changing melatonin levels are the culprit. Melatonin is a hormone that regulates sleep. Melatonin production increases in everyone during the winter when it's dark. However, in people with SAD, melatonin levels increase well beyond the norm. Studies have linked high melatonin levels to increased risk of depression. The final theory says that reduced levels of sunlight cause a decrease of serotonin. Serotonin is a neurotransmitter involved in the regulation of sleep, appetite, sex-drive, and mood. Serotonin has long been linked to depression, and most modern medications for depression target the serotonin system.
How is Seasonal Affective Disorder Treated?
SAD, like other forms of depression, can be treated with antidepressant medications and stress reduction techniques. However, there is also an approach tailored specifically to SAD: light therapy.
How Does Light Therapy Work?
Since a lack of daylight causes SAD, so the reasoning goes, adding daylight will solve the problem. Turns out, for most people, this is exactly what happens. In light therapy, the patient sits in front of a light box for anywhere between thirty minutes to two-and-a-half hours every day. The eyes must be open, but not focused on the box, so that the light can enter them indirectly. The box produces bright light similar to natural sunlight. When it hits the retina, the light causes a cascade of processes in the brain that eventually result in the regulation of circadian rhythms, decreased melatonin production, and increased serotonin production. The end result is elevated mood and reduction or cessation of all symptoms.
How to Choose the Best Light Therapy Box
Light therapy boxes can be bought over-the-counter in the United States. Check with your insurance company, some of them will reimburse you for the cost of a light box. Before buying a light box, there are a few key criteria to consider.
- Intensity. Light boxes vary in intensity from 2,500 to 10,000 lux. The brighter the light, the shorter the session required.
- UV exposure. Ultraviolet light can damage the eyes and skin. Look for a box that will produce minimal UV rays or one that shields you from them.
- Blue light exposure. Blue light can damage the eye. Look for a box with output further down the spectrum.
Light therapy works best in the early morning, so make sure to set aside some time during this time of day. Speak to your doctor before beginning light therapy. Side effects from light therapy are rare and minimal, but not everyone will profit from it. In some cases, it works best when combined with medications and lifestyle changes.
Photo Credit: thetorpedodog