] "Casting doubt on a basic principle of U.S. anti-drug ] policies, an independent study concluded on Monday that ] marijuana use does not lead teenagers to experiment with ] hard drugs like heroin or cocaine. ] ] The study by the private, nonprofit RAND Drug Policy ] Research Center countered the theory that marijuana acts ] as a so-called gateway drug to more harmful narcotics, a ] key argument against legalizing pot in the United States. ] ] " Study: Marijuana May Not Lead to Hard Drugs |