I don't want to sound as if I'm plugging them but I use my lightbox from, 0h, 07:45 until around mid-day and although I'm on 40mg a day of Citalopram for anxiety/PA/depression, I sleep well at nights, 22:00 'till 06:00.
I will admit, I sleep in the car on the way to work, in the car on the way home, have a nap for an hour of so as soon as I get home and am permanently tired, but at least I get an uninterrupted night's sleep.
Could it be the lightbox regulating the seratonin .... or just my body using up the nervous energy during the day and having nothing left to give come 22:00? I really don't know.
I know they're expensive but the £115 I spent on mine will have been worth it if I make it to Spring and natural light withought 'taking to my bed' and hibernating until the clocks go forward again.
Happiness and light to all,