So I'm usually just lurking here, but have to comment on this one. I have a 2 1/2 year old boy who has never slept well. The world's worst napper back when we tried to do naps and has a hard time falling asleep. More recently, he just couldn't fall asleep til about 11 pm or midnight.
Well this summer his big sister had evening swimming lessons, and he fell asleep on the way home half the nights. Huge difference when he got that full night sleep. I went to the pediatrician to talk about it, but he blew me off with "He'll get the sleep he needs. He's doing fine on this amount of sleep." Like I'm some silly mom who just wants a break and can't tell my toddler to go to bed. It's not that I'm just inconvenienced by his difficulty sleeping, it's for my son's sake. He does better than most little kids would do on 7 or 8 hrs sleep, and seeming to be functioning well. His big sister and baby brother would totally melt down on his former sleep schedule.
Also this summer he was diagnosed with PDD- NOS, on the mildest end of the autism spectrum. Googling autism & sleep showed that many parents with autistic and ADHD kids are using Melatonin. We started with 1 milligram of liquid melatonin every night, now reducing to .75. It's like a miracle. He is nodding off 45 min to an hour after he takes it. He is now getting about 11 hrs of sleep ( no nap).
He is doing so much better with 3 or 4 hours more sleep. He stumbles and falls less. He speaks more clearly. He has fewer tantrums. (But he IS still 2 and stubborn ;) ) Unless you had something better to compare it to, you'd say that our boy on less sleep is just how he is. When he had his evaluation, going on only 6 hrs sleep, he tested high on verbal abilities and very high on visual problem solving. BUT he's doing even better now. Before, he could do a 25 piece puzzle. After a week of good rest, he was doing 50 piece puzzles in 15 min! We've also noticed a difference in his creativity.
I just want to say how much sleep makes a difference. My son still sleeps less than his peers who get a full night a 2 hr nap. but i'd hesitate to say that a toddler getting 6-8 hrs just needs less sleep. It's worth trying melatonin, or herbal remedies, trying new routines, checking for food intolerances.