Treatment of Seasonal Affective Disorder with Green Light and Red Light

Department of Neurology, Jefferson Medical College, Philadelphia.
American Journal of Psychiatry (Impact Factor: 12.3). 05/1991; 148(4):509-11.
Source: PubMed


This study sought to determine whether an equal photon density of green light is superior to red light in treating seasonal affective disorder.
After recruitment through the media, 20 outpatients with seasonal affective disorder participated in a balanced-order crossover trial of 1 week of green light therapy compared with 1 week of red light therapy. Each treatment consisted of 2 hours of daily light treatment at home in the early morning. Ultraviolet light was excluded from both treatment conditions. The photon densities of the two treatments (2.3 x 10(15) photons/sec per cm2) were similar to those used in previous studies of therapy with 2500-lux white light. Fourteen patients completed the study. At least 1 week separated each treatment period to allow time for relapse. Effectiveness of treatment was assessed by analysis of variance of changes in ratings on the Hamilton Rating Scale for Depression.
Although patients' expectations of the two treatments were similar, green light induced greater antidepressant effects than red light. A Sequence by Color interaction was also demonstrated.
Green light provides a treatment effect superior to that of red light and similar to that seen in previous studies with white light. These results are consistent with the hypothesis that retinal photoreceptors mediate the antidepressant response in seasonal affective disorder. Identifying optimal wavelengths for light treatment is important in optimizing phototherapy efficacy.

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    • "Various studies have tried to distill the appropriate spectrum of light for BLT [14, 15, 21]. While some studies yield conflicting results, full spectrum white light (with filtered UV) has consistently been used for BLT. "
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    ABSTRACT: We present “Lightwear”, a series of garment-based, lightweight, light-emitting wearables designed to administer light therapy for on-the-go treatment of Seasonal Affective Disorder (SAD). Bright Light Therapy (BLT) has been used to treat SAD for more than 25 years. While light boxes continue to serve as the predominant method of treatment, it often requires a user to sit at a dedicated location for a sustained period of time (30-60 minutes), rendering therapy inconvenient and resulting in unsatisfactory compliance rates. To date, there have been few successful products developed for wearability and portability to ease the uncomfortable nature of light box treatment. However, new low-profile, light-emitting sources yield opportunities for less cumbersome textile integration and wearability. We explore the integration of light into textile substrates that focus on fashion-forward wearables which can,
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    • "The evening light, when given first, was comparable to morning light given first (Rafferty et al. 1990). Similarly, red light was almost as powerful an antidepressant as green light when it was the first treatment, while green light given first was superior to second treatment with red light (Oren et al. 1991). One explanation for these facts is the differential response of patients' psychology to the order of the optimal and less attractive treatment. "
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    Full-text · Article · Dec 2005 · Biological Rhythm Research
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    ABSTRACT: Bright white light has been successfully used for the treatment of depression. There is interest in identifying which spectral colors of light are the most efficient in the treatment of depression. It is theorized that green light could decrease the intensity duration of exposure needed. Late Wake Treatment (LWT), sleep deprivation for the last half of one night, is associated with rapid mood improvement which has been sustained by light treatment. Because spectral responsiveness may differ by age, we examined whether green light would provide efficient antidepressant treatment in an elder age group. We contrasted one hour of bright green light (1,200 Lux) and one hour of dim red light placebo (<10 Lux) in a randomized treatment trial with depressed elders. Participants were observed in their homes with mood scales, wrist actigraphy and light monitoring. On the day prior to beginning treatment, the participants self-administered LWT. The protocol was completed by 33 subjects who were 59 to 80 years old. Mood improved on average 23% for all subjects, but there were no significant statistical differences between treatment and placebo groups. There were negligible adverse reactions to the bright green light, which was well tolerated. Bright green light was not shown to have an antidepressant effect in the age group of this study, but a larger trial with brighter green light might be of value.
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