Many Think Marijuana Causes Little to No Harm, Study Finds
"In Colorado, the whole campaign to legalize was that marijuana is not as harmful as alcohol," Roffman noted. He said it's possible that, as a result, many people could "come to the conclusion that if attitudes change and laws change maybe there is nothing to worry about."
The changing public perception doesn't always align with medical opinion.
"That was a controversy from the very beginning," Dr. Patrick Fehling, an addiction psychiatrist at the University of Colorado Hospital Center for Dependency Addiction and Rehabilitation told ABC News. "Marijuana became legalized before a lot of its effect were fully understood."
Research on the drug has been limited and is now expanding, in part thanks to legalization and the tax dollars selling it has raised. But, so far, much of the research is actually "indicating potential for harm" from marijuana use, according to Fehling.
"There is a very big difference between recreational use and 'addictional' use," Fehling said. The "signs of addiction include tolerance and withdrawal, loss of control around your use, and consequences and problems in your life around your use."
"The use of medical marijuana is still highly controversial," he added, explaining that much of the research is still "anecdotal," based on what people self-report.
The number of American adults in the surveys who reported using marijuana increased from 10.4 percent to 13.3 percent over the 12-year period. The study, however, largely reflects self-reported data and may not account for how legalization has changed the way people report their marijuana use.
Also see Think it's harmless? Now nine in ten teens at drug clinics are being treated for marijuana use
