THC-Psychosis and Violence

The following is a list of violent incidents and mass shootings associated with marijuana use. Please use this file to share with your families and communities.


Two consultant psychiatrists today detailed how the psychosis led Diego Costa Silva, originally from Brazil, to believe that his wife, Fabiole Camara De Campos, was possessed by a serpent and was going to kill him. Costa Silva later removed her head to “make sure” that the serpent was dead, the Court heard.

Both psychiatrists agreed that the psychosis was not due to acute intoxication of the drug, but a more persistent illness of cannabis-induced psychosis, with the court hearing that the accused persisted in displaying psychotic symptoms eleven days after he was arrested and detained.

2023 –Woman Convicted of Involuntary Manslaughter Bryn Spejcher (DOB 01/25/91), of Thousand Oaks, was convicted by a jury of involuntary manslaughter in the
death of Chad O’Melia. Spejcher went to Mr. O’Melia’s apartment in Thousand Oaks, where both took several hits from a bong loaded with marijuana. Spejcher had an adverse reaction to the marijuana and suffered from what experts call Cannabis-Induced Psychotic Disorder. During that psychotic episode, Spejcher stabbed Mr. O’Melia multiple times, killing him. She also stabbed herself repeatedly.

2021. November – UK:  Jacob Notman, 28, stabbed his girlfriend 30 times after eating a marijuana brownie and pled guilty of manslaughter (cleared of murder due to lack of intent after having a psychotic break.

Man who stabbed partner 30 times after eating cannabis brownie cleared of murderStafford Crown Court told Notman did not know ‘what was real and what was not’ when he killed

2021 October – Pennsylvania, US- Babysitter Lavrius Watson, 26, stabbed and killed the mom of kids he was babysitting with a kitchen knife after they shared marijuana cookie.,marijuana%20cookie%2C%20according%20to%20police.

Babysitter Stabs Mom to Death, Blames it on Weed CookieLavrius Watson, 26, told police he suffered adverse effects from a weed cookie that made him stab 41-year-old Elizabeth Bennett to death inside her

2020 PITTSBURGH, PA – Marquis Brown smoked marijuana and began acting erratically, finally threw a chair at a window in his dorm room and jumped out the window before deputies could stop him.

Duquesne University Releases More Information On Student’s Death For ‘Clarity And Closure’Representatives from Duquesne University say they want to clear up any misinformation about the death of a student and put a stop to rumors that have been circulating

2019 Nov. – Canada –Adam Kehl, heavy cannabis use, beheaded father in cannabis-induced psychosis

Cannabis-induced psychosis blamed in beheading of father at Muskoka cottageWarning: Graphic and disturbing

2018 –  Canadian Lawyer Mark Phillips attacked a family with a baseball bat, suffering marijuana-induced psychosis, no jail time  

Marijuana-induced psychosis behind Toronto lawyer’s bat attack, judge rules with marijuana legalization on the horizon, the case raises questions about mental-health risks and new challenges for the legal

2017 – Edmonton Canadian Jason Dickout, 33, after using marijuana with his sister, had an episode of transient cannabis-induced psychosis and stabbed and killed his mom in 2017;  and pled guilty to manslaughter.

2015 – March- Easton Woodhead, Australia, smoked marijuana daily and had cannabis-induced psychosis when he stabbed a homeless man in 2014.  Found to have schizophrenia, NGRO, 25 years old detention in a psych facility.

Easton Woodhead suffering from marijuana-smoking psychosis in the lead-up to killing of homeless man Wayne PerryA former Melbourne Grammar School student charged with murdering a homeless man at Enterprize Park was suffering from a psychosis caused by marijuana use in the lead-up to the stabbing, a court has

Thamba became delirious after eating 6x recommended dose of marijuana cookie and fell off a balcony—charges were not pursued against the buyer of marijuana—contributing cause was listed as “marijuana intoxication” but seemed more like psychosis.

2007 – Thousand Oaks, CA – case was mentioned at trial for setting a precedent during Kris Mohandie’s testimony.  “Fox said at trial that Sharp was in a marijuana-induced and “fluctuating” psychosis. She described him as being troubled man who is faking mental illness.

Calvin Sharp sentenced to life for killing Newbury Park boyCalvin Sharp was sentenced to life without parole for the murder of a 6-year-old boy in Newbury Park on Aug. 12,

Controversial French case:  “The fact that this loss of control was linked to his voluntary smoking of cannabis over many years was, said the court, irrelevant. The root cause of a madness was not an issue in law, the judges said, as long as the madness was established, and it had been, by independent psychiatric analysis.

And so the Cour de Cassation ruled that Kobili Traoré should not stand trial but remain in the secure hospital where he has been kept ever since the murder.”

Sarah Halimi: How killer on drugs escaped French trial for anti-Semitic murder

THC and Mass Killers:

2/2023 – 43 yo Anthony McRae shot 8 people, 3 fatalities, before shooting himself during a rampage at Michigan State University. He was found to have alcohol at 0.04% and THC presence.

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 asking 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 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.

5/19 18-year-old 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 in his system.  McKinney began to abuse various substances like Xanax, cocaine, methamphetamine, alcohol, marijuana, and Adderall. 

1/19 – Dakota Theriot committed mass murder by shooting 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 and 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 had 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, and admitted using “a lot” of marijuana, resulting in him hearing to kill and attempting 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 workplace 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 behavior made around five years before the bombing. Police after Abedi left school, where he was known to have smoked marijuana and mixed with gangs in south Manchester

5/17: Richard Rojas, 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, a Paris bomber, was known as a 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. He was a chronic marijuana since age 16. The 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 (

Pentagon shooter John Bedell’s parents warned copsWASHINGTON – The two-gun Californian shot to death trying to attack the Pentagon had a history of mental illness…

 Other THC- psychosis/schizophrenia and violence references: 

1. Tell Your Children: The Truth about Marijuana, Mental Illness and Violence by Alex Berenson –,_Mental_Illness_and_Violence 

2. The attacker smoked cannabis – cases seen in the UK. Ross Grainer collected hundreds of news accounts of crimes and suicides committed under the influence of cannabis or cannabis-induced psychosis or schizophrenia to try to pressure the British government to look into the association between “skunk” cannabis and violence. – 

Jonathan Rosen’s recent book The Best Minds, about his friend Michael Laudor, who was brilliant but became schizophrenic and, while psychotic, killed his pregnant girlfriend and found NGRO, 32 minute discusses marijuana in relationship to schizophrenia—Michael used early—moms of schizophrenic sons see connection between cannabis and schizophrenia/psychosis

Friendship, Madness, and the Tragedy of Good Intentions (Ep. 75) — Randye KayeA story about friendship, love, and the price of self-delusion, The Best Minds explores the ways in which we understand—and fail to understand—mental illness. The 3 Moms in the Trenches of Schizophrenia talk with Jonathan on this episode www.randyekaye.comRandye Kaye – Author, Speaker, Actress, Voice TalentRandye Kaye is a world-renowned female voice talent for business and beyond. She is the author of two books; Hap…

A Voice Out of Nowhere by Janice Holly Booth is about Bruce Blackman, a Canadian who, in 1983, killed 6 members of his family after heavy cannabis use and a period of increasing psychotic delusions; high on cannabis during the killing, found NGRO and released under a new name after treatment.  Based on transcripts. 

Home Grown by Isaac Campos was his dissertation in which he researched news accounts in the Mexican press of 100s of incidents of marijuana-induced psychosis and/or violence, showing that marijuana was regarded as “When used in large doses it produced hallucinations, excitement, and loss of inhibitions leading to “delirium indistinguishable from insanity and often accompanied by violence.”[ leading to its being banned in 1920  calling it “one of the most pernicious manias of our people.”  Campos was a leftist who himself did not believe cannabis was dangerous and tried to discount his own research as evidence of biases on the part of the Mexicans rather than his own pro-cannabis bias!

A Review of Cases of Marijuana and Violence