MedicalResearch.com Interview with: Greg Midgette, PhD Assistant Professor Department of Criminology and Criminal Justice University of Maryland MedicalResearch.com: What is the background for this study? Response: This report estimates marijuana, cocaine, heroin, and methamphetamine use in the U.S. between 2006 and 2016 on three dimensions: the number of past-month chronic users per year, where "chronic" has previously been defined as consuming the drug at least four days in the past month, expenditure per drug among those users, and consumption of each drug. These measures are meant to aid the public and policy makers' understanding of changes in drug use, outcomes, and policies.   (more…)