It may be just historical happenstance that light therapy was first identified as a treatment for SAD, because many new applications are on the horizon. This may have wide ramifications for reducing the reliance on drugs in the future. But it takes an arduous clinical research effort to prove the effectiveness of new applications - consider that it took 15 years for the definitive trials of bright light therapy to come to completion.
Non-Seasonal Major Depression
Studies of light therapy for depression have not been limited to SAD. There is promising evidence that it may be effective in nonseasonal depression as well. A recent joint trial at Columbia University Medical Center and Wesleyan University indicates that patients with chronic depression - who have experienced virtually no relief in years - respond as well to light therapy as do patients with SAD. Dr. Daniel Kripke of the University of California at San Diego compared a set of placebo-controlled trials of bright light with antidepressant drug trials, and found the improvement rates to be similar. One major difference is that light appears to work within one week, while medications may take up to eight weeks to match the efficacy of light. Interestingly, light used in conjunction with medication appears to be superior to either one alone. Several European hospitals have already begun to administer light therapy alongside drug treatment.
Bulimia Nervosa
Bulimia is a troubling disorder in which patients eat unusually large amounts of food within a short interval of time ("bingeing"), often followed by purging, fasting or excessive exercise. Often, this occurs in private; even close family members may be unaware. And often, bulimia is accompanied by depression, which can be seasonal. In a pioneering controlled study, Dr. Ray Lam at University of British Columbia (Vancouver) showed that within two weeks of treatment, 10,000 lux bright light therapy for 30 minutes a day significantly reduced bingeing and purging, while the winter depression lifted. After four weeks of open treatment, bingeing reduced by 50 percent, purging by 42 percent. Still to be determined is whether bulimia is alleviated when SAD is not also present, and whether the dosing regimen for light can be enhanced to further reduce symptoms.
Premenstrual Syndrome
Another promising use of bright light is in the treatment of symptoms associated with PMS. Several clinical trials have been completed, focusing on light treatment in the luteal phase preceding menstruation, with significant relief of premenstrual depression. Not only has light therapy helped to improve the mood of PMS sufferers, but it appears to reduce the physical symptoms of "premenstrual tension." Several women have used the therapy for at least two years, with maintained positive response. While an optimum dosing regimen still needs to be determined, light therapy stands as an option particularly for women who have not responded to medication for PMS, or who have been bothered by medication side effects and discontinued treatment for that reason.
