A fairly well accepted treatment for SAD (Seasonal Affective Disorder) or winter depression is 30 – 60 minutes exposure a day to bright ‘Full Spectrum’ light (10,000 LUX) during the winter months. This has been found to be an effective method of dealing with this mood disorder.
A question that researchers at the University of South Carolina were interested in was whether such treatment would also be an effective for adults with high anxiety disorder. They tested the hypothesis with 33 high-anxious adults, exposing them to 45 minutes of bright full spectrum light every day for a period of four weeks.
They tested the subjects using a range of anxiety and depression indicators including blood pressure measures. There was no significant change in the individuals.
In short there is no evidence that bright light reduces anxiety.
Youngstedt, S. D., Kline, C. E., Ginsberg, J. P., Zielinski, M. R. and Hardin, J. W., (2011) Bright light treatment for high-anxious young adults: a randomized controlled pilot study. Depression and Anxiety