[Lazamataz]

Actually, to help you in finding the research in question, I think it involved the use of those machines used to measure brain activity. Normal and ADD people were given ritalin and the researchers compared brain wave activities.

Normal people taking ritalin had disruptions, but ADD people taking ritalin had modifications that got their 'brainprints' looking quite similar to normal people's.

Ritalin stimulates one particular area in the brain that is underutilized in ADD people. If there is no need for the ritalin, it does not concentrate there but instead causes a general stimulant effect to the entire brain. This is why normal people get an amphetamine result from taking ritalin, and ADD people do not.

[Zipporah]

You may find this interesting:

http://www.breggin.com/methylphen.html