Greenlotus, something which helps me (not ADHD, but take a long time to go to sleep because can't switch off) is listening to something on a timer (podcast or book or guided meditation). It helps me relax into sleep by engaging my interest, but because I'm lying down in the dark I'm more likely to fall asleep. Probably
not a magic bullet for your daughter, but might be helpful.
We've used melatonin for several years -- me, DS12 and DD9 -- and don't have any puberty happening here. It is a godsend for getting to sleep, for me when I have to go to work in the morning and for the kids when they have to get up for school. We haven't noticed any side effects whatsoever.
I had thought that unless there was some medical issue (AsD, in particular), that your should never take melatonin for more than three nights in a row because it would mess with your body's production of it. Is this no longer the recommendation? I use it on myself or kids roughly once a year if/when sleep times are way out of whack (on occasion bedtime will creep to close to 10pm, which leaves kids tired, but not tired enough to go to sleep at 8, or sometimes the lingering traces of jetlag will leave them tossing and turning in bed!), for one or two nights. Kids get half a tablet, I take a full one.
