Low-intensity blue-enriched white light (750 lux) and standard bright light (10 000 lux) are equally effective in treating SAD. A randomized controlled study

Meesters YDekker VSchlangen LJBos EHRuiter MJ.

University Center for Psychiatry, University Medical Center Groningen, Groningen, The Netherlands. y.meesters@psy.umcg.nl



BACKGROUND: Photoreceptor cells containing melanopsin play a role in the phase-shifting effects of short-wavelength light. In a previous study, we compared the standard light treatment (SLT) of with treatment using short-wavelength blue-enriched white light (BLT). Both treatments used the same illuminance (10 000 lux) and were equally highly effective. It is still possible, however, that neither the newly-discovered photoreceptor cells, nor the biological clock play a major role in the therapeutic effects of light on . Alternatively, these effects may at least be partly mediated by these receptor cells, which may have become saturated as a result of the high illuminances used in the therapy. This randomized controlled study compares the effects of low-intensity BLT to those of high-intensity SLT.

METHOD: In a 22-day design, 22 patients suffering from a major depression with a seasonal pattern (SAD) were given light treatment (10 000 lux) for two weeks on workdays. Subjects were randomly assigned to either of the two conditions, with gender and age evenly distributed over the groups. Light treatment either consisted of 30 minutes SLT (5000°K) with the EnergyLight® (Philips, Consumer Lifestyle) with a vertical illuminance of 10 000 lux at eye position or BLT (17 000°K) with a vertical illuminance of 750 lux using a prototype of the EnergyLight® which emitted a higher proportion of short-wavelengths. All participants completed questionnaires concerning mood, activation and sleep quality on a daily basis. Mood and energy levels were also assessed on a weekly basis by means of the SIGH-SAD and other assessment tools.

RESULTS: On day 22, SIGH-SAD ratings were significantly lower than on day 1 (SLT 65.2% and BLT 76.4%). On the basis of all assessments no statistically significant differences were found between the two conditions.

CONCLUSION: With sample size being small, conclusions can only be preliminary. Both treatment conditions were found to be highly effective. The therapeutic effects of low-intensity blue-enriched light were comparable to those of the standard light treatment. Saturation effects may play a role, even with a light intensity of 750 lux. The therapeutic effects of blue-enriched white light in the treatment of SAD at illuminances as low as 750 lux help bring light treatment for SAD within reach of standard workplace and educational lighting systems.

BMC Psychiatry. 2011 Jan 28;11:17.

Full Text http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3042929

Randy Clare

Randy Clare

Randy Clare brings to The Sleep and Respiratory Scholar more than 25 years of extensive knowledge and experience in the sleep and pulmonary function field. He has held numerous management positions throughout his career and has demonstrated a unique view of the alternate care diagnostic and therapy model. He is considered by many an expert in the use of a Sleep Bruxism Monitor in a dental office. Mr. Clare's extensive sleep industry experience assists Sleepandrespiratoryscholar in providing current, relevant, data-proven information on sleep diagnostics and sleep therapies that are effective for the treatment of sleep disorders. Mr Clare is a senior brand manager for Glidewell Dental Laboratory his focus is on dental treatment for sleep disordered breathing.

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