Shedding New Light on "Lite" Therapy
by Larry Pederson
Seasonal Affective Disorder (SAD) is a medically recognized sub-type of clinical depression. Characterized by abnormal mood episodes with a seasonal component, an estimated 5% of Americans experience SAD, especially in the winter months. Another 25% of Americans suffer with the winter blues, a common term for the milder form of SAD.
Typically, symptoms appear as the days become shorter, increase in severity—peaking in January or February—and decreasing as the days grow longer, to completely disappear by April each year.
WHAT CAUSES SAD?
Its exact cause isn't known; however, researchers believe it is due to an over-secretion of melatonin when we are awake. Melatonin is the naturally occurring hormone that tells us it's time to sleep and keeps us asleep during the night.
Melatonin is secreted by the tiny pineal gland in the brain when we're exposed to very little or no light. For most, melatonin is released between 9 and 11 pm, peaking between 3 and 5 am, and gradually dropping off with the approach of morning. For those with SAD or winter blues, melatonin secretion continues after waking. Scientists believe that there isn't enough early morning sunlight during the winter months to signal the brain that it's daylight. Normal interior lighting is not bright enough to send this crucial signal.
Those with SAD feel the need to sleep three to five hours longer than usual and lose interest in work, school, or social activities. Appetites, especially for carbohydrate-rich, comfort foods like chocolate and pasta, increase as does weight between the months of October and March. Shifts in mood, difficulty concentrating, as well as a decreased libido may be experienced.
Historically, SAD was treated with anti-depressant medication such as Prozac®. However, undesirable side-effects are common with these medications. Fortunately, another treatment option has been gaining popularity with both clinicians and patients: light therapy.
WHAT IS LIGHT THERAPY?
It involves the use of a bright light source that shines directly at the user's eyes. Though the mechanism isn't completely understood, light therapy is known to suppress melatonin, while increasing the "feel-good" chemical serotonin level in the brain in a manner similar to SSRI (Selective Serotonin Reuptake Inhibitor) anti-depressants.
Treatment involves daily exposure to a bright light source of accepted therapeutic intensity, with exposure duration of a set period (usually 15 to 60 minutes, as early as possible upon waking) and distance from the light source. Recent research indicates that light of certain wavelengths, especially in the "blue" part of the spectrum, is most effective. Users may perform routine tasks such as reading, eating, exercising, or working at a computer, while receiving light therapy treatment.
Researched at leading institutions worldwide for over 20 years, light therapy has been found to be completely safe and effective. In a recent three-year study conducted at four centers in Canada, light therapy was shown to be as effective as Prozac® for SAD and, more importantly, demonstrated earlier onset of benefits and lower rates of adverse events than the medication.
Early light boxes were large and bulky. A smaller, more portable device, The Litebook®, is now available in the U.S. Using white Light Emitting Diode (LED) technology, The Litebook consumes 1/10th the power of traditional light boxes, produces no UV rays and virtually no heat, and emits light in the exact peak wavelengths shown to be most effective for suppressing melatonin, resulting in a shorter treatment time: 15-30 minutes per day.
Typically, users recognize when they have received a sufficient light treatment, most often by feeling of heightened alertness, energy, and/or mood. Children (8+ years), teenagers, and seniors have also responded well. As with all forms of therapeutic treatment, it is recommended that individuals consult their health care professional regarding the appropriateness of light therapy.
Light therapy is increasingly the treatment option chosen by physicians and psychiatrists for patients suffering from SAD. Many U.S. patients have been able to obtain a prescription for light therapy and receive coverage from insurance companies for the purchase of a light-therapy device.