The evidence seems convincing enough at first blush: studies show that 99 percent of illicit drug users tried marijuana before they did any other drugs. But on its own, this line of thinking actually is pretty tenuous: we could also safely assume that 99 percent of illicit drug users also tried coffee, or soda, or chocolate milk before moving on to stronger substances.
New research out this month in the Journal of School Health could shed some light on this question. A team of researchers from Texas A&M and the University of Florida examined data from from 2,800 U.S. 12th graders interviewed for the Monitoring the Future study, an annual federal survey of teen drug use. They wanted to establish which substances teens typically used first.
They give away their findings in the title of their paper: “Prioritizing Alcohol Prevention: Establishing Alcohol as the Gateway Drug and Linking Age of First Drink With Illicit Drug Use.” They found that “the vast majority of respondents reported using alcohol prior to either tobacco or marijuana initiation.”