[reitanqild]

I believe you. That said it seems to vary wildly.

From what I have witnessed it even varies with type of the same stimulant from person to person, even within a family. (In a case I know all too well the recipient get tongue swelling as well as clenched jaws[0] on R XR at 40mg/day but has absolutely no issues with doses from 40 - 80 mg/day of the standard one. Oh, and the other person in this study, the brother of the first, went into spiraling weight loss at 60mg/day but prefer XR.)

Also playfulness seems to be preserved in these two cases. The best explanation I can come up with is: lowers the "interesting" threshold so that driving according to the speed limits is less intensely boring etc.

[0]: of course this can be reactions to additives of XR but they are commonly referred to as side effects of R itself.