A multicenter study of the light visor for seasonal affective disorder: No diference in efficacy found between two different intensities

Abstract

Fifty-five patients with winter seasonal affective disorder (SAD) were treated with a light visor, a newly developed, mable light-delivery system, in a controlled parallel agn. A dim (400 lux) visor was compared with a Wight (6000 lux) visor for either 30 or 60 minutes in the.oming for 1 week. Response rates for these two treatments were 36% and 56°%, respectively, the duration f treatment sessions did not affect outcome. There was no evidence that the brighter visor was superior in efficacy to the dimmer one. Significantly greater relapse occurred following withdrawal of the dimmer visor. Alternative explanations for these findings are that the light visor is acting as a placebo or that it is equally effective over a wide range of intensities. © 1993 American College of Neuropsychopharmacology.