More Americans are using marijuana, and fewer people think that regularly doing so is harmful. The new study shows that from 2002 to 2014, the number of American adults who used marijuana in the last year increased by 10 million and the number of people who used it daily increased by more than four million. Interestingly, the researchers also observed a drop—50% to 33%—in the number of people who thought that smoking marijuana once or twice a week was harmful.
