My 7-year-old son (with high functioning autism & ADHD) keeps waking up through the night and I really believe it's contributing to him having a cruddy day at school almost every day. I always hear him talking at night...I go into his room and he's either acting out an action scene from a movie or pretending to be a teacher in a classroom. He also tosses and turns, and is usually up at 3-4 am and unable to get back to sleep.
On the few nights that he really sleeps through the night, the next day usually goes really smoothly. On nights that he struggles with sleep, the next day is terrible.
I read that kids with autism generally produce Melatonin at odd times through the day, not at night as should be the case, so autism and sleep disorders seem to go hand and hand....and it might mean that he needs a melatonin supplement.
I've had him scheduled for a visit to a sleep clinic at the children's hospital here in Denver and in a couple weeks he will be undergoing a sleep study and I'll be sure to report the results. It's possible someone else out there may read this and decide to examine that possibility with their child as well....especially the ones that have an ADHD diagnosis.