“In a paper in the winter issue of the Journal of Policy Analysis and Management, two researchers — D. Mark Anderson of Montana State University and Daniel Rees of the University of Colorado at Denver — report that legalization of marijuana for medical purposes has been associated with reductions in heavy drinking, especially among 18- to 29-year-olds, and with an almost 5 percent decrease in beer sales. In addition, the increase in the legal drinking age from 18 to 21 seems to encourage greater marijuana use among people under 21, usage that drops sharply when they reach the legal drinking age.”

– http://www.nytimes.com/2013/11/04/opinion/marijuana-and-alcohol.html?ref=todayspaper