sor, substance abuse researcher and the study’s lead author.
The results “show people can use marijuana without harms, but there are risks,” she said, adding that more research on causes of problematic use is needed.
Dr. Wilson Compton, deputy director of the National Institute on Drug Abuse, said other research has shown similar trends but that the sharp increase found in the surveys is striking. Prevalence of dependence “is of great concern” to public health officials, he said.
Recreational use is legal in four states — Alaska, Colorado, Oregon and Washington — and many more have moved to reduce penalties for marijuana possession. Proposed laws supporting recreational use have been introduced in at least 21 states this year, according to the National Conference of State Legislatures.
Medical marijuana programs have been approved in 23 states.
. Online: JAMA Psychiatry: http:// bit.ly/1LnNeCK