Bright white light therapy has been used to treat seasonal affective disorder (SAD) for more than 20 years.
Although it remains a mainstay of treatment, in the past few years researchers have investigated ways to improve and refine light therapy, reports the November 2008 issue of the Harvard Mental Health Letter.
Improvements are necessary for three reasons. First, light therapy doesn't work for everyone. Studies have reported that 50% to 80% of patients achieve complete relief and that remission may depend upon carefully individualized timing of light exposure. Second, dosing remains a major question. The recommendation for 30 minutes of daily exposure to 10,000 lux is based on average response to white light. Finally, side effects, while mild for many patients, may be more of a concern for others.
Dr. Michael Miller, editor in chief of the Harvard Mental Health Letter, notes that investigations are now under way to see if changing the timing or type of light therapy might improve response or reduce side effects. Some areas of study: