Understanding Marijuana: A New Look at the Scientific EvidenceMarijuana is the world's most popular illicit drug, with hundreds of millions of regular users worldwide. One in three Americans has smoked pot at least once. The Drug Enforcement Agency estimates that Americans smoke five million pounds of marijuana each year. And yet marijuana remains largely misunderstood by both its advocates and its detractors. To some, marijuana is an insidious stepping stone drug, enticing the inexperienced and paving the way