Cannabis and the Violent Crime SurgeAllysia Finley

2022 Jul-Aug

How do marijuana legalization policies affect violence rates?

The researchers found that recreational marijuana legalization was associated with about a 20% increase in self-harm injuries among males under the age of 40. The increase was greater when cannabis products were available for commercial purchase through dispensaries.

Association of Cannabis Use With Self-harm and Mortality Risk Among Youths With Mood Disorders

January 19, 2021

Conclusions and Relevance  Cannabis use disorder is a common comorbidity and risk marker for self-harm, all-cause mortality, and death by unintentional overdose and homicide among youths with mood disorders. These findings should be considered as states contemplate legalizing medical and recreational marijuana, both of which are associated with increased CUD.

Fact or Faction Regarding the Relationship between Cannabis Use and Violent Behavior

December 2021

Conclusions: Considering that cannabis is the most commonly consumed illicit drug and with increasing legalization of cannabis throughout the world, it is important to understand its effects on violence and its consequences for public health and safety.1,9 The findings from this review suggest that, on the basis of the current literature, frequent cannabis use is a potential risk factor for violence and aggression, particularly in individuals who may have a unique susceptibility for engaging in violent behavior (e.g., certain individuals with SPMI). More standardized and empirical research is required. Findings from such studies will help to clarify misconceptions surrounding cannabis use and are of high relevance to clinical settings and public health and safety.,illness%20versus%20the%20general%20population).

Association Between the Use of Cannabis and Physical Violence in Youths: A Meta-Analytical Investigation

27 May 2020


These results demonstrate a moderate association between cannabis use and physical violence, which remained significant regardless of study design and adjustment for confounding factors (i.e., socioeconomic factors, other substance use). Cannabis use in this population is a risk factor for violence.

A Review of Cases of Marijuana and Violence

March 2020

The main scope of this paper was to inform the general public about the relationships between marijuana and violence in the general population and in individuals with mental illnesses, as recent findings do link marijuana with cases where psychosis was present. This article is a case review and not a research study; therefore, the chief limitations regard inferences that can be made from a case study. However, the findings suggest a further need for research on marijuana and violence. The authors of this paper did not intend to take sides regarding the legalization of marijuana. The focus was public health in regards to marijuana

Association Between the Use of Cannabis and Physical Violence in Youths: A Meta-Analytical Investigation

May 2020

Conclusions: These results demonstrate a moderate association between cannabis use and physical violence, which remained significant regardless of study design and adjustment for confounding factors (i.e., socioeconomic factors, other substance use). Cannabis use in this population is a risk factor for violence.

Published Online:27 May 2020

Association Between the Use of Cannabis and Physical Violence in Youths: A Meta-Analytical Investigation

Epub 2020 May 27.

Conclusions: These results demonstrate a moderate association between cannabis use and physical violence, which remained significant regardless of study design and adjustment for confounding factors (i.e., socioeconomic factors, other substance use). Cannabis use in this population is a risk factor for violence.

United States Secret Service- National Threat Assessment Center -Mass Attaches in Public Spaces 2019

Nearly half of the attackers (n = 17, 46%) had a history of using illicit drugs (e.g., cocaine, methamphetamine, LSD, Ecstasy) or misusing prescription medications (e.g., Xanax, Adderall, Vyvanse). For two-fifths of the attackers (n = 15, 41%), the use of these substances and/or alcohol and marijuana may have reached the level of abuse causing negative consequences in their lives, including criminal charges, academic failures, court-ordered treatment, and eviction. One of the attackers later claimed to have no memory of his attack, alleging he had been drinking heavily at the time and had blacked out. In this sample of attackers, a significant relationship was observed between substance abuse and domestic violence.12 Ten attackers (27%) had histories of both domestic violence and substance abuse.

Marijuana Is More Dangerous Than You Think

Alex Berenson

Over the past 30 years, a shrewd and expensive lobbying campaign has made Americans more tolerant of marijuana. In November 2018, Michigan became the tenth state to legalize recreational cannabis use; New Jersey and others may soon follow. Already, more than 200 million Americans live in states that have legalized marijuana for medical or recreational use. Yet even as marijuana use has become more socially acceptable, psychiatrists and epidemiologists have reached a consensus that it presents more serious risks than most people realize.,moc.liamg%40rohtuanosnerebxela

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Marijuana use is associated with intimate partner violence perpetration among men arrested for domestic violence

Oct 2017

In summary, findings demonstrated marijuana use positively associated with psychological, physical, and sexual IPV perpetration among men arrested for domestic violence and court-referred to BIPs. These findings were present even after accounting for other known risk factors for IPV perpetration. We believe continued investigation into the associations between marijuana use and IPV is important due to the public health, legal policy, and treatment implications that would result from this line of research. Continued research utilizing rigorous methodological designs, such as daily diary designs, is needed to further understand the association between marijuana and IPV perpetration. Finally, pending replication and extension, findings suggest BIPs may want to target reductions in marijuana use, which may have the concurrent benefit of reducing IPV.

Marijuana Violence and Law

January 2017

Conclusion: According to research studies, marijuana use causes aggressive behavior, causes or exacerbates psychosis and produce paranoia. These eوٴects have been illustrated through case studies of highly publicized incidents and heightened political profiles. These cases contain examples of repeated illustrations of aggression, psychosis and paranoia by marijuana users and intoxication.
Ultimately, without the use and intoxication of marijuana, the poor judgment and misperceptions displayed by these individuals would not have been present, reducing the risk for actions that result in senseless deaths.
Import to these assertions, is that the current marijuana is far more potent in THC concentrations, the psychoactive component. Accordingly, and demonstrated in direct studies, more potent marijuana results in a greater risk for paranoid thinking and psychosis. In turn, paranoid behavior increases the risk for paranoid behaviors and predictably associated with aggressive and violent behaviors.
Marijuana use causes violent behavior through increased aggressiveness, paranoia and personality changes (more suspicious, aggressive and anger). Recent illicit and “medical marijuana” (especially grown by care givers for medical marijuana) is of much high potency and more likely to cause violent behavior.
Marijuana use and its adverse effects should be considered in cases of acts of violence as its role is properly assigned to its high association. Recognize that high potency marijuana is a predictable and preventable cause of tragic violent consequences.

The relationship between marijuana use and intimate partner violence in a nationally representative, longitudinal sample.

Nov 2011

Consistent marijuana use (OR = 1.85, p < .05) was related to an increased risk of intimate partner violence perpetration. Adolescent marijuana use, particularly consistent use throughout adolescence, is associated with perpetration or both perpetration of and victimization by intimate partner violence in early adulthood. These findings have implications for intimate partner violence prevention efforts, as marijuana use should be considered as a target of early intimate partner violence intervention and treatment programming.

7/22 – 21 yo Bobby Crimo III, the suspected mass shooter who gunned down seven people and injured dozens at the Independence Day parade in Highland Park, Illinois , was a stoner who lost touch with reality per his friends.

5/22 – 18 year old Salvador Ramos shot 19 children and 2 teachers dead in a classroom in Uvalde, Texas.  His co-worker stated he would often talk about how much he despised his mother and grandmother, whom he told her did not let him smoke weed or do what he wanted.  He started picking fights with co-workers again and bragging about quitting his job, saying he no longer needed the money, Ms. Rodriguez said. He told her and others that he was going to “act out” in a big way and they would all hear about it, she said.  “He wanted to cause trouble,” she said. “He wanted to cause destruction.”

12/21 – Lyndon James McLeod, was in the middle of a targeted gun rampage that would leave five people dead in Denver and Lakewood.  He seemed to get his money from a marijuana growing operation.

11/21 – Ethan Crumbly shot and killed 4 students and injured 7 others at Oxford HS in Michigan.  His parent bought him a gun for his birthday.  He wrote in his journal of his failing grades and mental problems (“seeing demons and asked for help”) and witnesses told investigators marijuana was often used in the house.

11/21 – Darrell Brooks smelled of marijuana when being arrested following driving a vehicle through Kenosha, WI during a Christmas parade killing six victims and injuring 60 more.

10/21 – Jacob Bergquist shot and killed two people and injured 4 at the Boise Towne Square mall.  Bergquist had a felony conviction in Illinois for theft and a  and a misdemeanor conviction in Wisconsin for marijuana possession.

2/21 Tristan Griffin shot and killed 3 people before turning the gun on himself and committed suicide.  He was THC positive in his toxicology.

3/20: Joaquin Roman shot and killed four people at a Kum & Go convenience store before committing suicide in Missouri.  He told fellow gamers that he had recently run out of marijuana shortly before the shootings.

8/19: Connor Betts shot and killed nine people, including his transgender brother, and wounded 17 others near the entrance of the Ned Peppers Bar in the Oregon District of Dayton, Ohio. Betts was fatally shot by responding police. He  was addicted to several different drugs including heroin, meth, Xanax, prescription drugs and marijuana since high school.

5/19: DeWayne Craddock, who was a disgruntled city employee, fatally shot 12 people and wounded four others before he was fatally shot by responding police officers in Virginia Beach.  He was seen outside of his apartment smoking marijuana.

5/19 18 yo Devon Erickson and 16 yo Alec McKinney entered STEM school in CO and shot killing one student and injuring 8.  Erickson was found to have THC and cocaine is his system.  McKinney began to abuse various substances like Xanax, cocaine, methamphetamine, alcohol, marijuana, and Adderall.

1/19 – Dakota Theriot’s committed mass murder by shooting of 5 people including his parents and girlfriend before being captured.  He had a history of smoking weed for years and being involved in violent attacks.

4/18 – Travis Reinking was convicted of 8 counts of first degree murder shooting people at a Waffle House in Antioch Tennessee while naked wearing nothing but a green jacket.  He claimed to be not guilty by reason of insanity with schizophrenia causing delusions and hallucinations.  A day before the shooting he stole a BMW and wrote in a journal he has plans to drive to Colorado, hang out with friends and smoke marijuana.

11/18 – Ian David Long killed 13 people in a shooting at the Borderline Bar and Grill in Thousand Oaks, CA his toxicology was positive for THC, caffeine and nicotine

2/18 – Nicholas Cruz killed 17 people at Marjory Stoneman Douglas High School in Parkland, Florida admitted using “a lot” of marijuana resulting in him hearing to kill and attempted suicide multiple times Parkland shooting suspect Nikolas Cruz spoke of ‘voices,’ says he attempted suicide (

11/17 – Kevin Neal, a known marijuana grower, used a semi-automatic rifle and 2 handguns at 7 shooting sites (including an Elementary School) leaving 4 dead in Red Bluff, CA Neal used a semi-automatic rifle and 2 handguns at 7 shooting sites (including an Elementary School) leaving 4 dead in Red Bluff, CA His toxicology was positive for only THC.   Tehama County shooting: Kevin Neal ‘off the hinges,’ neighbors say (

6/17: John Neuman shot 5 people then himself at his former work place in Orlando.  He has past convictions for marijuana possession, DUI and beating a former co-worker.

5/17: Salman Abedi the Manchester England bomber had calls about his erratic behaviour made around five years before the bombing to Police after Abedi left school, where he was known to have smoked marijuana and mixed with gangs in south Manchester

5/17: Richard Rojas was a troubled man with a history of drunken driving bolted from his maroon Honda Accord after his deadly midday rampage in Times Square that left one person dead and 20 others injured. He later told another officer, “I smoked marijuana. I laced the marijuana with PCP,” according to the complaint

9/16: WA Cascade Mall Shooter Arcan Cetin blamed cannabis for his behavior

6/16: Omar Mateen Orlando night club shooter admitted to using marijuana and steroids New Details Emerge About Orlando Nightclub Shooter Omar Mateen – ABC News (

11/15: Robert Dear Planned Parenthood gunman in Colorado moved to CO from North Carolina for marijuana

10/15 Noah Harpham shot 3 people in a random attack and was shot and killed by Police.  He had a positive toxicology only for THC.

11/15: Brahim Abdeslam Paris bomber was known marijuana dealer from his café in Molenbeek Brussels The Belgian Connection: How Brahim Abdeslam Became an ISIS Suicide Bomber (

8/15: Jody Herring, mother on THC (the psychoactive component in marijuana) pills for pain, shot and killed Vermont Social worker and 2 others State employees remember Lara Sobel’s commitment to children – VTDigger

7/15: Chattanooga TN shooter Mohammad Abdulazeez killed 4 Marines and a sailor, was a heavy user of marijuana Details Emerge About Alleged Chattanooga Shooter’s Life | HuffPost Latest News

6/15: Dylnn Roof shoots 9 parishioners dead in Charleston, South Carolina, was an admitted marijuana user with schizophrenia

4/14: Richard Kirk, Colorado father of 3, shoots his wife in the head while she is talking to the 911 operator after eating marijuana laced candy Denver Man Who Said Marijuana Made Him Kill His Wife Gets 30 Years (

1/14: Mall in Columbia (MD) shooter marijuana user Darion Aguilar killed 2 and then himself Maryland Mall Shooter was a Pothead – Accuracy in Media (

4/13: Boston Marathon bombing, both Tsarnaev brothers were heavy marijuana users Lessons from Boston bombings about marijuana, education – The San Diego Union-Tribune (

12/12: Jacob T Roberts in Clackamas Town Center OR killed 2 seriously injured 1 and then killed himself a chronic marijuana since age 16 Clackamas Town Center shooter carried 145 rounds, fired 17 shots –

9/12 Andrew Engeldinger shot 6 co-workers in Minnesota before committing suicide.  His parents report him using alcohol and marijuana and becoming depressed and schizophrenic.

7/12: Aurora, Colorado theater shooter, James Holmes, was reported to be a marijuana user Marijuana abuse common thread in mass killings – Vermont Daily Chronicle

1/11: Tuscon Massacre convict Jared Loughner was a habitual pot user Marijuana’s Role in the Arizona Shooting | HuffPost Latest News

3/10: Pentagon shooter John Bedell’s  history of mental illness and marijuana abuse.  He grazed 2 people at the Pentagon killing no one. Pentagon shooter John Bedell’s parents warned cops – New York Daily News (