[xadrez]

I believe the difference between Ritalin and Concerta is Concerta has a time release mechanism, so you take one in 12 hours and it releases slowly, which mitigates the speedy feeling you'd get from taking straight ritalin. They both contain the same active ingredient, Methylphenidate, as someone mentioned before.

Thus, just like oxycontin, a "breaking" of the time release mechanism before ingestion has a vastly different effect. I cut one in half one time back in college not knowing this, as I had to write a 20 page term paper (my GF at the time had a presciption. Lets just say that I got completely spastic and jittery and chain smoked about 25 cigarettes in 4 hours. Got my paper done, but it wasnt pleasent. I guess what Im trying to say is dont break them in half unless you like feeling like you have an espresso IV.