i think its true...."sleep begets sleep." i don't have any official dx ADHD, but i'm sure my 5 y/o kindi kiddo would meet criteria. he seems to not need much sleep...up till 8 or 9 if i let him but always up again by 630 or 7am. but if I help him sleep more, consistently he is SO much better. not wild and impulsive, not clumsy and hurting himself all teh time. can sit and focus. my older dd and yonger ds follow a similar pattern, although nto to the extreme of ds1.
as far as getting more sleep...for us, its routine, routine routine. every single night. no exceptions. (that is so hard for me, as WOTH mama). we aim for:
230 or 300 - 500 big outdoor play time, pool, etc.
500 - 530 bath
530 - 600 dinner/clean up
615 - 700 or maybe 715 reading time (he loves to read and be read too...would sit much longer if we would allow).
715 brush teeth, take melatonin 1 mg (not always, just on occasion if we are way off and behind on sleep) and lights off. i have room darkening shades.
this is MURDER on these long summer nights, but ds is like a whole new person. otherwise he will sometims crash for an afternoon nap starting anywhere from 2 - 5, wake an hour later cranky as can be. then up late, up early and so on.
he is at his best when his days are "play hard, sleep hard." we also homeschool, so we have the flexibility in our days.
I think regardless, sleep hygeine is SO important. no suger/caffeine in afternoon or evening. no movies/tv/screens/lights in room or after dinner. routine with whatever you like...bath, jamies, song, prayers, story. the routine teaches the body and mind sleep is coming. and consistent bed time and wake time.
loving my dh and our littles (dd ~ 11 yrs, ds ~ 9 yrs, ds ~ 7 yrs, dd ~ 5 yrs and baby brother ~ 20 mo)