There is something called delayed sleep phase syndrome (DSPS), which I have read is fairly common among people with ADHD. It basically means that your natural body rhythms want you to sleep from about 4 am to noon, instead of 11-7 or whatever hours "normal people" sleep. In other words, people with DSPS have trouble getting to sleep if they try to go to bed at a decent hour, but once they get to sleep they can sleep the night away (and half of the day too.) I have ADHD and I think I have this - I have always tended to be a "night owl," and if I don't have to get up early for work, my natural schedule tends to get later and later, until I am going to bed at 4 or 5 and sleeping until 2 in the afternoon. I also find that Concerta helps me get going in the morning - apparently this is fairly common, as a lot of people with ADHD seem to have difficulty coming awake in the morning.