Study Challenges Claims That Medical Marijuana Leads to Higher Crime Rates

Researchers at the University of Texas at Dallas have found no increase in crime in states that legalized medical marijuana. They analyzed rates of murder, rape, assault, robbery, burglary, larceny and auto theft.

Medical marijuana legalization may be associated with lower rates of certain offenses, such as assault and murder, the researchers reported. They looked at crime rates in every state between 1990 and 2006. During that period, 11 states legalized medical marijuana. The researchers used FBI data to analyze rates of various types of crime, and found none increased in the states that legalized medical marijuana, HealthDay reports.

The results appear in the journal PLoS One.

“We’re cautious about saying, ‘Medical marijuana laws definitely reduce homicide.’ That’s not what we’re saying,” study author Robert Morris said in a university news release. “The main finding is that we found no increase in crime rates resulting from medical marijuana legalization. In fact, we found some evidence of decreasing rates of some types of violent crime — namely homicide and assault.”

The researchers plan to examine how the legalization of recreational marijuana in Washington state and Colorado affects crime rates in those states, once that information is available.