First thing that came to mind about the study was that if participants have to wake up at certain time every day, and they have to be still for 30 minutes, the

First thing that came to mind about the study was that if participants have to wake up at certain time every day, and they have to be still for 30 minutes, they are likely to use that eating breakfast. For me having fixed sleep rhythm and eating breakfast are two things that help with moody periods. So it could be that the side effects are more important than the light itself. If it's true that this helps, but doesn't really cure. Then it might be best used on healthy people. So they don't ever get depressed.