Dr. Nora Volkow, Director of the National Institute on Drug Abuse (NIDA), urged lawmakers recently to resist legalizing marijuana.
At a House subpanel hearing, she said marijuana can act as a gateway drug.
Speaking before the House Energy and Commerce Committee's Oversight and Investigations subpanel, Volkow said studies show changes that occur in brain chemistry after people use marijuana, alcohol or tobacco can prime them for harder drugs, The Hill reports.
She told the House panel that many people think marijuana is harmless because they have heard about its potential medicinal benefits, but that more research is needed.
In a message on the NIDA website last year, Volkow wrote, "Regular marijuana use in adolescence is part of a cluster of behaviors that can produce enduring detrimental effects and alter the trajectory of a young person's life—thwarting his or her potential. Beyond potentially lowering IQ, teen marijuana use is linked to school dropouts, other drug use, mental health problems, etc. Given the current number of regular marijuana users (about 1 in 15 high school seniors) and the possibility of this number increasing with marijuana legalization, we cannot afford to divert our focus from the central point: Regular marijuana use stands to jeopardize a young person's chances of success—in school and in life."