I use lighting for circadian rhythm control, otherwise I have delayed sleep phase and de-sync from the clock completely every couple months. So, BRIGHT "daylight" blue-white indoor lighting from 7am to 5pm, every day of the year. It helps a LOT. Of course with bipolar we have to be careful, but using the light box and/or sufficiently powerful lighting during the entire day is really underrated, IMO, especially in winter.

I'm a huge lighting nerd, PM me with any lighting questions, I welcome it.