One argument made against the legalization of marijuana for medical use is that it will increase crime, either by drawing criminals to dispensaries or by leading users down the path to other drugs, such as cocaine and heroin. However, a recent study may cause that claim to fade away like a puff of smoke.

Findings published last week in the journal PLOS One show no noticeable increase in crimes such as  homicide, rape, robbery, assault, burglary, larceny, or auto theft. In fact, there appear to be declines in violent crimes, such as homicide and assault, in areas where medical marijuana is legal.

The study doesn’t claim that the legalization of medical marijuana is the cause of the decrease in violent crime. However, according to the researchers, “while it is important to remain cautious when interpreting these findings as evidence that MML [medical marijuana legalization] reduces crime, these results do fall in line with recent evidence and they conform to the longstanding notion that marijuana legalization may lead to a reduction in alcohol use due to individuals substituting marijuana for alcohol. Given the relationship between alcohol and violent crime, it may turn out that substituting marijuana for alcohol leads to minor reductions in violent crimes that can be detected at the state level.”

Or, according to the study, it could just be that more people are accepting of medical marijuana use. “Perhaps the more likely explanation of the current findings is that [medical marijuana legalization] laws reflect behaviors and attitudes that have been established in the local communities. If these attitudes and behaviors reflect a more tolerant approach to one another's personal rights, we are unlikely to expect an increase in crime and might even anticipate a slight reduction in personal crimes.”

Other legal changes governing marijuana use have cut arrests in other areas. In California, arrests of juveniles for marijuana possession dropped 61% when the penalty was reduced from misdemeanor to infraction status.

-Steve Straehley

To Learn More:

The Effect of Medical Marijuana Laws on Crime: Evidence from State Panel Data, 1990-2006 (by  Robert G. Morris, Michael TenEyck, J. C. Barnes and Tomislav V. Kovandzic, PLOS One)

No, Legalizing Medical Marijuana Doesn’t Lead To Crime, According To Actual Crime Stats (by Emily Badger, Washington Post)

Pot Decriminalization Has Dramatically Lowered Juvenile Arrests (by Ken Broder, AllGov California)