You Need More Lumens
A recent Cochrane review found very little high quality evidence in either direction:<p><a href="http://www.cochrane.org/CD011269/DEPRESSN_light-therapy-prevention-winter-depression" rel="nofollow">http://www.cochrane.org/CD011269/DEPRESSN_light-therapy-prev...</a><p>It's not clear to me why light therapy is considered as a well-researched treatment.