Like many pwp, I had a long history of depression before DX. I noticed it was seasonal "SAD" and purchased an official "light box" for treatment. The light box worked great. What I liked the most was that the light therapy works within a few days if it in fact is going to work. Light "burns off" melatonin very quickly and it would seen that the greater problem is light exposure or contamination "burning off" available melatonin when one is supposed to be sleeping.