Although ingenious theories have been advanced to explain this paradoxical effect of methylphenidate, the mechanism of its action is unknown.
A Concerta capsule acts as a minipump, gradually pushing methylphenidate out through tiny, laser-drilled holes in its coating.
Novartis has received the FDA's preliminary approval to market another, more refined form of methylphenidate that requires a smaller dosage than the current formulation.
David Steel in BBC News NHS QIS Chief Executive Dr David Steel said: "The increase in the prescribing rate for ADHD drug Methylphenidate, commonly known as Ritalin, raises the important issue of what constitutes the appropriate level of prescribing in Scotland. We can see...