In the New York Times science section today (August 31), Weill Cornell Medical College psychiatrist Richard Friedman writes about how illicit drugs like cocaine and methamphetamine may permanently reduce a person's capacity for enjoying life's splendors. These drugs, he notes, activate the brain's reward system by releasing dopamine. However, he observes, the brain then tries to compensate for the drug's presence, and it does so by becoming less sensitive to dopamine. The brain may end up with a "less responsive reward circuit," Friedman writes, which never fully repairs itself even after the drug use stops. The result is that the person may then be condemned to "endure a dulled life."
All of that may be true. But here is what is missing from this article. Ritalin and the other stimulants used to treat ADHD in children also activate the dopamine system. Ritalin, in fact, does it in much the same manner that cocaine does, and with equal potency. (The difference is that Ritalin is not cleared from the body as quickly as cocaine, and thus a dose of Ritalin has longer-acting effects than cocaine.) In response, the stimulant-using brain undergoes changes that make it less sensitive to dopamine release -- it is trying to compensate for the drug's presence.