I don't know a whole lot about how they work but I do have a light and I've found it really useful in the wintertime when there's less/hardly any sunlight. Just be careful because I've found mine gives me headaches if I leave it on too long. I only use it about an hour a day, and it took a while to feel any effects, but once I did I really noticed a difference. The light + meds was a HUGE help in getting over the worst of my depression, so I think it's definitely worth investigating.