Brain imaging studies and blood tests conducted by researchers at Massachusetts General Hospital showed that the widely prescribed once-a-day ADHD drug Concerta acts differently in the body than the rapid-release form of Ritalin, even though both drugs contain the same active ingredient -- the stimulant methylphenidate.
As expected, the tests showed that the delayed-released drug took longer to reach peak effective levels within the brain and body and the regulating effects lasted longer than with the rapid-release version of the stimulant.
And adult study participants without ADHD who took the rapid-release form of the stimulant were more likely to report feeling a pleasant effect from the drug than participants who took the timed-release stimulant.
"We know that drugs that cause euphoria are potentially abusable, and euphoria requires rapid delivery to the brain," says Thomas J. Spencer, MD, who led the research team. "The ability to show that rate of brain delivery may determine abuse potential is important to our understanding of the safety of different formulations."
Different Types of Abuse
According to a nationwide study of drug abuse patterns among adolescents, known as the Monitoring the Future Survey, Ritalin abuse among high-school seniors doubled between 1999 and 2004, from 2.5% to 5.1%.
Spencer says some of this increase may be due more to misuse of the drugs by people without ADHD who want to exploit their stimulant effect, rather than by serious drug users looking to get high.
Serious abusers often crush the rapid-release form of the stimulant and then snort it like cocaine to create a high. The long-acting stimulants have less potential for this type of abuse, Spencer says.
"We can't really say what percentage of abusers are trying to get high and how many may be taking the drug orally to stay up and cram for a test," he says.