Texas Study: Medical Marijuana Legalization Doesn’t Lead to More Crime

The legalization of medical marijuana has sparked debate across the nation for decades.

Some have argued that medical marijuana’s legalization will lead to higher crime rates. But according to a new study at UT Dallas, legalization of medical cannabis is not an indicator of increased crime.

It actually may be related to reductions in certain types of crime, said Dr. Robert Morris, associate professor of criminology and lead author of the study published in the journal PLOS ONE.

“We’re cautious about saying, ‘Medical marijuana laws definitely reduce homicide.’ That’s not what we’re saying,” Morris said. “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 UT Dallas team began its work in summer 2012 after repeatedly hearing claims that medical marijuana legalization posed a danger to public health in terms of exposure to violent crime and property crime.

The study tracked crime rates across all 50 states between 1990 and 2006, when 11 states legalized marijuana for medical use: Alaska, California, Colorado, Hawaii, Maine, Montana, Nevada, Oregon, Rhode Island, Vermont and Washington. Since the time period the study covered, 20 states and Washington, D.C., have legalized marijuana for medical use.

Using crime data from the FBI’s Uniform Crime Report, the researchers studied rates for homicide, rape, robbery, assault, burglary, larceny and auto theft, teasing out an effect for the passing of medical marijuana laws.

None of the seven crime types increased with the legalization of medical marijuana.

Robbery and burglary rates were unaffected by medical marijuana legalization, according to the study. These findings run counter to the claim that marijuana dispensaries and grow houses lead to an increase in victimization because of the opportunities for crime linked to the amount of drugs and cash that are present.

Morris said the models accounted for an exhaustive list of sociodemographic and econometric variables that are well-established links to changes in crime rates, including statistics on poverty, unemployment, college education, prison inmates and even the amount of beer consumed per person per year. Data came from the U.S. Census Bureau, the Bureau of Economic Analysis and the Bureau of Labor Statistics.

“The results are remarkable,” Morris said. “It’s pretty telling. It will be interesting to see what future studies hold.”

Once data are available, the researchers plan to investigate the relationship between recreational marijuana legalization and crime in Washington and Colorado, where the legalized marijuana marketplace is taking shape.

While it’s too soon to say if there are definitive drawbacks to legalizing marijuana for medical purposes, Morris said, the study shows that legalization does not pose a serious crime problem, at least at the state level.

“This new information, along with continued education of the public on the realities of the negative aspects of smoking marijuana — which there are considerable negative attributes — will make the dialogue between those opposed and in favor of legalization on more of an even playing field,” Morris said. “It takes away the subjective comments about the link between marijuana laws and crime so the dialogue can be more in tune with reality.”

UT Dallas doctoral student Michael TenEyck, assistant professor Dr. J.C. Barnes and associate professor Dr. Tomislav V. Kovandzic, all from the criminology program, also contributed to the study as co-authors.

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7 thoughts on “Texas Study: Medical Marijuana Legalization Doesn’t Lead to More Crime”

  1. i understand how beneficial the use of medical marijuana maybe benefit a lot of people, i am more concerned with the long term effects such as addiction. Wont addiction be a major problem after medical marijuana is legalized. i know a couple of people who use marijuana day after day, i suspect addiction. and where there’s addiction, there is obviously going to be crime.

  2. Any more propaganda that you want to spew, Metin Gunduz? Cannabinoid metabolites stay in the body for a long while. Drivers who test positive for Cannabis could very well have used it a week prior to the accident. Alcohol has always been, continues, and will always remain the first and foremost intoxicant that causes automobile accidents. Many people illegally also drive under the influence of pain killers and other man-made anti-anxiety medications which cause a fair amount of traffic accidents. That being said, no one is advocating for people intoxicated on any substance to drive.
    Your propaganda will not work any more. People are not nearly as gullible (with the help of much more information available) than they were in the days of Harry Anslinger and his other greedy and racist partners in crime.

  3. “Metin Gunduz” is an industry-paid troll of Big Alcohol. Don’t be fooled. If cannabis were legalized and alcohol were criminalized, so much needless death and destruction, both physically and socially, would be avoided. Stoned drivers behave like your grandma behind the wheel, drunk drivers hurdle down the road like the Fast and Furious, possibly killing your actual grandma. Stoned couples at home get the munchies and watch TV, drunk couples are more likely to end up in fights, often ending in domestic violence.

    • John ; Alcohol and Marihuana both together are the `first` step substances to `advance and experiment further` with so called `heavy duty ones` you know what I mean . There is no substance or chemical has ever been more harmful to any human society in this Planet Earth than good old Alcohol for thousands of years . It simply `eliminates` the ` higher cortical functions of any brain ` and regresses that individual , back to millions of years of evolutionary time … It simply eliminates `fear and anxiety and coping with the cold realities of daily real life we all live in ` most people experience these fears quite naturally , of course it is just being human . And trying to escape from these fears has never been the answer , we never learned and probably never will in the future too . So adding one more substance over already legalized ` one major bad thing` –alcohol that is – and making it additional variety of individual`s –legal choice- to use his/her hearts content freely and openly , and creating `option ` to chose as if these substances only harm is limited to the individual person who happen to chose to use them – as personal free choice – socially , and forgetting about the `fundamental fact` that the WHOLE SOCIETY SUFFERS AS A CONSEQUENCES of these so called – legalized availability of these substances and chemicals – despite to the CONTRARY `proven facts `OF TRUE MEDICAL AND SOCIAL HARM TO THE INDIVIDUAL WHO USES THEM AND THE WHOLE SOCIETY AND OTHER INDIVIDUALS HE/SHE LIVES WITH OR ASSOCIATE WITH ; without any reasonable doubt whatsoever is simply called – ignorance- . And every society of course has the right to decide their own destiny ,and free choice one way or other at the end ; it has always been like that throughout thousands of years human history and will be so in the future too in positive or negative ways , knowingly or unknowingly and innocently as bystanders . Intelligent and wise politicians guide and shepherd their people wisely to a better future ; corrupt ones simply destroy it as always has been the case throughout human history with no exception ever seen so far will be so in the future too .

  4. Lol wut Metin Gunduz? I like how whenever a study has the “gall” to be neutral or have a positive aspect to Marijuana or Marijuana legalization the prohibitionist lose their minds. Your fear mongering about crime is untrue and unfounded. Change the argument. Tell them how the gate way theory is incorrect. Why do you hate the children? Reasonable article on dispensaries impact on crime: Respond with copy pasta of an unrelated auto study (that didn’t single out Marijuana but listed it with alcohol and other drugs). Science isn’t your friend prohibitionist.

    • Joseph Burnett ; Let me give you further information regarding Harmful Health effects of Marihuana Smoking for Children ; OTHER than FATAL CAR ACCIDENTS :
      First ;Marihuana smoking cause the same harm `inhalation of CO –Carbon monoxide- “ poison that is” created by any incomplete burning of wood , it is the same gas kill during house fires , the molecule of CO binds Oxygen carrying molecule of blood 210 times stronger and replaces available Oxygen by a `poison` CO molecule and it will NOT release it easily . There is NO CIGARETTE or MARIHUANA SMOKE FILTER IN THE WORLD to filter out the CO (Carbon monoxide gas molecule of smoker ) . This is the molecule damages and kills your vessels inner cells called `endothelial cells` causes –atherosclerosis- so called `hardening/narrowing/blocking of your blood vessels` and most importantly impairs the function of brain cells by poisoning with Carbon monoxide . You lose your `short term memory function ` when you smoke with NO exception . In other words if you look at any written short numbers 4 or 5 random digits for 1 minute duration and go another location and try to remember the numbers you just read after waiting only 5 minutes , believe me if you are a `smoker` and CO (Carbon monoxide on board in your circulation) you will NOT ABLE TO REMEMBER THE NUMBERS CORRECTLY .. You have to take the page with you to look at it again sadly that is the truth …
      Second ; Cannabis use causes `delusions` and even precipitate psychotic episodes this fact well documented with studies
      http://adai.uw.edu/marijuana/factsheets/mentalhealth.htm Mental Health and Marihuana

  5. Lets come to the real FACTS other than `rumors` and poorly designed studies regarding the substance of Marijuana and `false and misconstrued information` rather than `reality` .When 11 states legalized marijuana for medical use: Alaska, California, Colorado, Hawaii, Maine, Montana, Nevada, Oregon, Rhode Island, Vermont and Washington.
    It is a serious trend indeed , unfortunately people and politicians are misinformed about the real danger of Marihuana use .

    Lets go to the REAL FACTS HERE : ( Some may not consider RELATED CAR ACCIDENTS as CRIMES ) but believe it or not they are strictly related with `Marihuana use` and SOCIETY SUFFERS AS A WHOLE from the usage of these substances , whether Crime related or Car Accident related does not make any difference in reality ..


    Trends in Alcohol and Other Drugs Detected in Fatally Injured Drivers in the United States, 1999–2010 (* )

    Feb. 4, 2014 (Health Day News) — The legalization of marijuana is an idea that is gaining momentum in the United States, but there may be a dark side to pot becoming more commonplace, a new study suggests.

    Fatal crashes involving marijuana use tripled during the previous decade, fueling some of the overall increase in drugged-driving traffic deaths, researchers from Columbia University’s Mailman School of Public Health report.

    “Currently, one of nine drivers involved in fatal crashes would test positive for marijuana,” said co-author Dr. Guohua Li, director of the Center for Injury Epidemiology and Prevention at Columbia. “If this trend continues, in five or six years non-alcohol drugs will overtake alcohol to become the most common substance involved in deaths related to impaired driving.”

    The research team drew its conclusions from crash statistics from six states that routinely perform toxicology tests on drivers involved in fatal car wrecks — California, Hawaii, Illinois, New Hampshire, Rhode Island and West Virginia. The statistics included more than 23,500 drivers who died within one hour of a crash between 1999 and 2010.

    Alcohol contributed to about the same percentage of traffic fatalities throughout the decade, about 40 percent, Li said.
    But drugs played an increasingly prevalent role in fatal crashes, the researchers found. Drugged driving accounted for more than 28 percent of traffic deaths in 2010, up from more than 16 percent in 1999.

    Marijuana proved to be the main drug involved in the increase, contributing to 12 percent of 2010 crashes compared with 4 percent in 1999.


    Abstract :

    Drugged driving is a safety issue of increasing public concern. Using data from the Fatality Analysis Reporting System for 1999–2010, we assessed trends in alcohol and other drugs detected in drivers who were killed within 1 hour of a motor vehicle crash in 6 US states (California, Hawaii, Illinois, New Hampshire, Rhode Island, and West Virginia) that routinely performed toxicological testing on drivers involved in such crashes. Of the 23,591 drivers studied, 39.7% tested positive for alcohol and 24.8% for other drugs. During the study period, the prevalence of positive results for non alcohol drugs rose from 16.6% in 1999 to 28.3% in 2010 (Z = −10.19, P < 0.0001), whereas the prevalence of positive results for alcohol remained stable. The most commonly detected non alcohol drug was cannabinol, the prevalence of which increased from 4.2% in 1999 to 12.2% in 2010 (Z = −13.63, P < 0.0001). The increase in the prevalence of non alcohol drugs was observed in all age groups and both sexes. These results indicate that nonalcoholic drugs, particularly marijuana, are increasingly detected in fatally injured drivers.

    ( * ) http://aje.oxfordjournals.org/content/early/2014/01/27/aje.kwt327.abstract?sid=310cc5fd-bfdb-4cf9-a3d9-7f60790a3cd5

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