Darkness (the real thing, where you can't see your hand in front of your face) at constant times is the cure for insomnia. (Take it from someone who suffered insanely for decades, and only suffers from "painsomnia", now, from time to time.) So if a placebo convinces you you'll sleep if you turn the lights off, and you do turn the lights off, the placebo will be a real help. Or you could just do the (true) darkness thing. PS red light at night is okay, it doesn't trigger your pRGCs.