Medical marijuana legalization may lead to lower homicide rates, study finds

Keep Westword Free
I Support
  • Local
  • Community
  • Journalism
  • logo

Support the independent voice of Denver and help keep the future of Westword free.

During the debate over regulating medical marijuana dispensaries, opponents frequently suggested that the presence of such shops would cause crime to rise. Numerous studies have debunked these predictions and a new University of Texas Dallas inquiry does, too -- but with a twist. Researchers note that crime rates related to some of the most serious offenses, including homicide, actually fell in states after medical marijuana was legalized, although they stop short of making a definitive causal connection.

"The Effect of Medical Marijuana Laws on Crime: Evidence from State Panel Data, 1990-2006," credited to Robert G. Morris, Michael TenEyck, J. C. Barnes and Tomislav V. Kovandzic, appears in the journal PLOS ONE. We've included the complete article below, but an abstract summarizes the findings like so: "Results did not indicate a crime exacerbating effect of MML [medical marijuana legalization] on any of the Part I offenses. Alternatively, state MML may be correlated with a reduction in homicide and assault rates, net of other covariates."

The italicized "may" above appears in the original -- and the word appears again in a passage that drills a bit deeper into the results. Here's an excerpt:

With one exception -- forcible rape -- states passing MML laws experienced reductions in crime and the rate of reduction appears to be steeper for states passing MML laws as compared to others for several crimes such as homicide, robbery, and aggravated assault. The raw number of homicides, robberies, and aggravated assaults also appear to be lower for states passing MML as compared to other states, especially from 1998-2006. These preliminary results suggest MML may have a crime-reducing effect, but recall that these are unconditional averages, meaning that the impact of the covariates and other factors related to time series trends have not been accounted for in these figures.

Also included in the piece are a series of graphics depicting the rates of assorted crimes in medical marijuana states. As you can see, the rates for homicide, robbery, aggravated assault and burglary are all down over the test period. In contrast, those related to forcible rape, larceny and auto theft remain above the "prior to medical marijuana" line, although generally not by a huge margin. This study joins others that have documented little to no negative societal impact related to medical marijuana. In February, for instance, our William Breathes detailed University of Colorado Denver research showing that "a medical marijuana dispensary in the Denver area doesn't have any more impact on its neighborhood than does a coffee shop or a drugstore."

Continue for more about the latest study, including the complete document. Such reports have become more the rule of late than the exception. As Breathes pointed out, "similar studies in Colorado and California have come up with the same conclusions in recent years." He specifically cites "a 2012 study on dispensaries in Sacramento using police-compiled crime statistics," which "showed no increase in crime whatsoever near the shops," despite the fact that "any crimes that did occur tended to receive more media attention than a similar robbery of a dry cleaner or gas station."

Among those organizations taking notice of the University of Texas Dallas study is Law Enforcement Against Prohibition (LEAP), whose executive director, former Baltimore narcotics cop and past Westword profile subject Neill Franklin, released the following statement: "It must be difficult to be an opponent of marijuana reform. They can't make arguments against legalization based on logic and facts so they must constantly resort to fear-based hypotheticals and anecdotes that keep getting proved wrong by systematic study. I feel for them. I really do."

Here's the complete article.

The Effect of Medical Marijuana Laws on Crime

Send your story tips to the author, Michael Roberts.

More from our Marijuana archive circa February 19: "Medical marijuana stores impact neighborhoods in Denver no more than coffee shops, study says."

Keep Westword Free... Since we started Westword, it has been defined as the free, independent voice of Denver, and we would like to keep it that way. Offering our readers free access to incisive coverage of local news, food and culture. Producing stories on everything from political scandals to the hottest new bands, with gutsy reporting, stylish writing, and staffers who've won everything from the Society of Professional Journalists' Sigma Delta Chi feature-writing award to the Casey Medal for Meritorious Journalism. But with local journalism's existence under siege and advertising revenue setbacks having a larger impact, it is important now more than ever for us to rally support behind funding our local journalism. You can help by participating in our "I Support" membership program, allowing us to keep covering Denver with no paywalls.

We use cookies to collect and analyze information on site performance and usage, and to enhance and customize content and advertisements. By clicking 'X' or continuing to use the site, you agree to allow cookies to be placed. To find out more, visit our cookies policy and our privacy policy.


Join the Westword community and help support independent local journalism in Denver.


Join the Westword community and help support independent local journalism in Denver.