Research Study of Treatment for Winter Depression With Different Colors of Light

Optimizing Light Wavelength for Treatment of Seasonal Affective Disorder

The specific aim of this study is to test the hypothesis that light stimuli concentrated around 467 nm will evoke a significantly stronger therapeutic response in SAD patients compared to light stimuli concentrated around 657 nm at an equal photon density.

The secondary objective of this study is to determine the efficacy of different colors and levels of light in order to optimize therapeutic benefit, while also minimizing side effects and maintaining safety of light exposure.

Studies report as many as 1 out of every 5 Americans is affected by mild to severe Seasonal Affective Disorder (SAD, winter depression). Although the exact cause of this condition is unknown, bright light has proven to be an effective therapeutic treatment for many people with SAD. The light sources that have been traditionally used for treatment of SAD produce white light with great variability in the balance of wavelengths that are emitted across the visible spectrum. Although several studies have attempted to test the effectiveness of different wavelengths for treatment of SAD, the devices used in those studies employed broad bandwidths of light. With the technological advancements in light emitting diodes (LEDs) the production of new light therapy equipment with much narrower bandwidths of light is possible. Side effects of exposure to traditional white light therapy for SAD have included hypomanic activation, irritability, headache, eyestrain and nausea. We hypothesize that when the wavelength of light therapy is optimized, it should be feasible to elicit strong therapeutic benefits with lower light intensities and fewer side effects. Previous studies, approved by the Jefferson IRB and successfully completed by our laboratory have shown that some colors of light are more effective in treating SAD than other colors.

Inclusion Criteria:

• Clinical diagnosis of Seasonal Affective Disorder
• Over 18 years old
• Stable sleeping pattern with a bedtime no later than 1 a.m.

Exclusion Criteria:

• Pregnant women
• Concurrent psychiatric illness that would preclude compliance with the protocol
• active suicidal or homicidal ideation or plan
• variable psychiatric illness (i.e. rapid cycling disorder or severe premenstrual syndrome)
• individuals with substance abuse or dependence who have not been in remission for at least one year
• individuals taking photosensitizing medications
• individuals with macular degeneration or other ocular conditions which might be adversely affected by light
• less then six weeks after onset of psychotherapeutic treatment