New meta-study on light therapy effects by  Penders TM et al.;

Prim Care Companion CNS Disord. 2016 Oct 20;18(5). doi: 10.4088/PCC.15r01906.

The study by Penders et al. compared randomized clinical trials with nonseasonal depressed patients (N=457 patients). The results showed significant improvement with bright light therapy (> 30 minutes and > 5000 lux) in conjunction with pharmacotherapy, when compared to pharmacotherapy alone.