Today’s Cannabis Linked To Violence – New Study

By June 8, 2020 Media Release

Media Release 8 June 2020
A large study just published by a team from Montreal University in Canada has found that people who regularly smoke cannabis are almost three times more likely to commit a violent offence as those who abstain from the drug.

The paper entitled “Association Between the Use of Cannabis and Physical Violence in Youths: A Meta-Analytical Investigation” and published in the American Psychiatric Association’s (APA) American Journal of Psychiatry did a meta-analysis of 30 studies which covered 296,815 people up to the age of 30.

The study found that over time, prolonged cannabis use profoundly alters the brain, making the user less able to control their temper, and that addicts may also suffer from withdrawal symptoms, making them irritable and prone to lashing out. Psychiatrist Professor Sir Robin Murray, a world-leading expert on the neurological impact of the drug, was quoted in the media saying that the link between cannabis use and violence was a ‘neglected area’.

The researchers say that while ‘the [scientific] literature has shown that cannabis use may lead to violent behaviours and aggression; however, this association has been inconsistent’ – with some studies showing a relationship and others not – their meta-analysis found users were more than twice as likely (2.15 times) to have committed a violent offence as non-users. Among ‘persistent heavy users’, the risk of violence was 2.81 times higher.

This follows a study published just last month in the journal JAMA Psychiatry which found that the use of high-potency cannabis was associated with a significant increase in the frequency of cannabis use, likelihood of cannabis problems, and likelihood of anxiety disorder. In addition, high-potency weed users are more likely to use weed at least once a week, twice as likely to have used illicit drugs within the past 12 months, and more than three times as likely to be tobacco smokers. Significantly, the study defined high potency as “typically ≥10% THC”. According to the proposed New Zealand legislation, THC levels (the psychoactive chemical in cannabis) are initially set at 15% THC for smoking.

“This latest study simply reinforces what we already know. Today’s cannabis is a significantly harder more potent drug causing greater harms than the pot of the 90’s or earlier. The use of cannabis is associated with increased risks of a number of adverse outcomes including educational delay, welfare dependence, increased risks of psychotic symptoms, major depression, increased risks of motor vehicle accidents, increased risks of tobacco use, increased risks of other illicit drug use, and respiratory impairment,” says spokesperson Aaron Ironside.

“At a time when New Zealand’s mental health system is bursting at the seams, why would we go and legitimise a mind-altering product which will simply add to social harm?”

Join the discussion 37 Comments

  • Mata Tekii says:

    No to dope cannabis

  • Irene says:

    Nope to dope cannabis

  • Matthew says:

    Nope to dope cannabis

  • E Frank says:

    How does cannabis use impact the unborn child?

  • Lynette says:

    what a load of crap people who drink alcohol of violent people who smoke dope and not also you go without a cigarette or anything you used to having for a few days you going to be a little crabby this is just a load of garbage

  • Dean says:

    The issue is the socio-economic position these people are in (poor, financialy
    Stressed, lack of education opportunities and stigmatized by others who think less of them combined with the astronomical consumption of alcohol, which is encouraged by the lobbyist corporates..that is the primary cause of violence…Only a very small percentage have mental health issues and that can be addressed with kindness and support

  • Duran says:

    What a bunch of absolute nonsensical rubbish. There are hundreds of other studies that disprove this kind of garbage. I hope you idiots fight this hard to get alcohol made illegal because the rate of alcohol relate domestic violence is 85%.

  • Dave says:

    good report. 👍

  • Thisis shit says:

    This is complete crap and false advertising. You guys are idiots who obviously have not tryed it.
    Bet you have a beer or wine after work tho.
    Go away with you pharmaceutical lovin asses and let us live our own way.

  • Red says:

    Can you stop scaremongering and making up bullshit stories. This story is crap and you know it. You are just trying to make cannabis users look bad. You want to end violence ban alcohol. That causes more issues that cannabis ever will. You are not doing yourselves any favours either by printing this crap. You make yourselves liok like idiots and to be honest you make it look like you are scared of a little plant that’s been around for millions of years. It’s been around longer than the mythical god and jesus. It’s just a plant.

  • Red says:

    I know of midwives that tell pregnant mums to smoke it (one cone a day type thing) during pregnancy to help with morning sickness. They wouldn’t be suggesting it if it wasn’t safe

  • Ants Clay says:

    Good luck peddling your lies

  • Dan Collett says:

    It doesn’t – My kids are living proof. They are very bright kids – their school reports are always dominated with A’s, and I have been a regular Cannabis consumer for over 23 years.

  • Dan Collett says:

    This is false propaganda designed to dupe the public into the age old MYTH that cannabis turns an otherwise peaceful person into an axe weilding murderer – it simple isn’t true – I am a regular user of over 20 plus years and I don’t have a violent bone in my body! In fact – I have seen first hand how cannabis calms an otherwise angry individual that had too much caffeine that morning, right down to the point where they are jovial, happy and compassionate towards other people. Cannabis is an amazing plant with boundless potential. Everything comes with risk though – should everyone use Cannabis? NO – of course not. Should a person be labelled a criminal because they enjoy safely using Cannabis? NO -of course not… and it’s that point that we are trying to change with this referendum. The penalty far outweighs the alleged crime in this country and it is highly debateable that it should even be classed as a crime in the first place. Even our PM Jacinda Ardern has said publicly – ‘What we have been doing up until now simply hasn’t worked. That’s why we are having this referendum’. It’s about creating a fairer society where we are ALL included. At the moment, society has been trained us not to accept a large part of society simply because they use Cannabis. Cannabis prohibition was founded on racism and needs to end immediately. It disproportianally affects Maori. Why do we still support a racist law here in NZ? It’s time to leave that all in the past. Vote YES

  • Dan Collett says:

    If you vote no you are supporting a racist law. Cannabis prohibition was founded on Racism and it disproportionally affects Maori. Vote YES for a fairer society. Responsible Use – Not Abuse

  • Dan Collett says:

    If you vote no you are supporting a racist law. Cannabis prohibition was founded on Racism and it disproportionally affects Maori. Vote YES for a fairer society. Responsible Use – Not Abuse

  • Dan Collett says:

    If you vote no you are supporting a racist law. Cannabis prohibition was founded on Racism and it disproportionally affects Maori. Vote YES for a fairer society. Responsible Use – Not Abuse

  • Dan Collett says:

    If you vote no you are supporting a racist law. Cannabis prohibition was founded on Racism and it disproportionally affects Maori. Vote YES for a fairer society. Responsible Use – Not Abuse

  • Karl Greenall says:

    What utter rubbish, if Google fact checked this it would be deleted faster than a Trump Tweet! Your research has no substance what so ever. l look forward to the day the law is changed in favour of cannabis and people stop using depresants such as Alcohol which as we all know causes endless harm and violence … FACT!

  • mark samuels says:

    Is this propaganda being funded by the National party by any chance…what a pack of lies you are spreading,shame on you.

  • Mikey says:

    Say Nope to Dope is founded by paedophiles so don’t trust anything they say about cannabis. They should be in Jail!

  • Margret Phillips says:

    This is rubbish, my husband was an excessively violent man, without alcohol. I introduced him to cannabis, he calmed down, became a nice person!! This report is basically scaremongering. I use it to elevate chronic pain, it is a great medicant, and I certainly don’t believe I am addicted. I don’t use it on a daily or weekly basis, only when it gets to the point the prescribed medication doesn’t work!!!!

  • Kathy Ellison says:

    Nope to dope. My vote and will not be persuaded as seen with my own eyes harm caused by it. It is called dope for a reason…..don’t be one!

  • Johnny blaze says:

    What a load of BS. Not one person I have ever met gets violent when smoking cannabis let alone 3 TIMES MORE VIOLENT.
    That why you see most of the blazers at home on the couch in their sweat pants on a Friday night watching the family guy, whilst the boys who have polished off a bottle of bourbon are cruising the clubs looking for a fight…. get real

  • Deon Aldridge says:

    That’s a violent sounding reply Red.

  • Deon Aldridge says:

    That’s a violent sounding reply Red.

  • Deon Aldridge says:

    I am very pleased you got away with it. Some of us have not had you lucky experience with children pickled in weed and the result Schizophrenia and ultimately a graphic suicide. Are you people willing to name the midwife that recommended this as they need to be educated on the other result from your good luck.

  • Deon Aldridge says:

    I am genuinely interested in your health and well being. As someone at the coal face and helping people who are or have been regular users I observe the following in 100% of these people disproportionately to others in society; poor learning ability, financial hardship unless they run a tinny house. Poor teeth and gum disease, hacking coughs and poor lung health, bad diets, stench on their clothes and body from poor hygiene, bed wetting as adults, in attention and disconnect from work, study and especially relationships (one regular user said “not present “ and I suppose the reason it is used?), increased rates of depression and Schizophrenia and definitely aggression when just talking about trying life clean. When wasted most afflicts are chilled but when needing a fix they are irritated at best but psychotic and dangerous at worst. I don’t need a study or data I have real life experience and the permanent damage to my property to prove it, funeral memories, police reports, coroner enquires (ongoing). to substantiate my view. I care deeply for these / you people trapped in this weed prison and know that you think by normalising it you will feel better about yourself and the sad reality that you can only get through the day getting wasted. To get from addicted to clean will be very hard for most but the benefits for you and your loved ones fantastic. I don’t want to make your self loathing worse but pretending this is safe and making money out of something patently destructive is not an improvement.

  • Merran says:

    This “study” was a meta-analysis study. It took more than 11,000 past studies, selected less than half a single percent of them and then reached some rather dubious conclusions which are contrary to every major study where real participants were involved. Not one single participant was involved in the meta-analysis, not one young person (user or non-user) was interviewed, studied or followed by the researchers. They simply took the data for a tiny sample of studies they hand selected and then reached conclusions entirely at odds with the original research findings of each of those studies. Talk about smoke and mirrors!

  • Tom says:

    Anyone who has used weed, and that’s most people, know from their own experience that it is more likely to calm than enrage. As someone above said, you’re making yourselves look silly. The only people you will persuade with this are people who have probably never voted for anything progressive.

  • DAVID SAUL says:

    I’m more concerned with religion screwing up peoples’ brains. Religion leads to wars and discrimination and violence far more than cannabis so this party is a drug pusher of the very worst kind.

  • Chris says:

    I know right ….coffee contains a psychoactive drug that causes me to throw things if I dont have one when I want one………

  • Jack says:

    Just for that voting NO

  • Jack says:

    Only crimminals vote yes

  • Whi says:

    longer than Jesus ??? sorry, but you don’t know what you’re talking about there….”in the Beginning, God……”
    “millions of years “….that’s an evolutionary and wholly inaccurate statement/comment ! i don’t expect you’ll bother to research further or to believe me, but you know, calling people (like)idiots and “scared” when you haven’t met them, most likely, does nothing to enhance one’s perspective on you, either. “crap” ????? Mmmmmmnnnn ,actually “No!”- either you are totally misinformed or you simply don’t care about other people – for instance, children affected by ‘dope’ users, parents, siblings, caregivers…teachers under the influence, .etc. etc, drivers under the influence….on and on,
    and yes! Violence!! i have SEEN and heard this myself MANY times sadly – I do agree that (use of ) alcohol is a major problem however, and needs to be addressed- unfortunately that Industry (and its promotion) is WAY out of control- due to their corrupt money magnates running it!!- who also Don’t care about anything /anyone more than the $$$$$$$$$$$ rolling in to their pockets and greedy bank accounts!!! ~and it’s not “just a plant” – if that were so- no-one would be battling over the control of it , making money from it and telling lies about the Influence of it on TEENS esp. and so many others… have a great day!

  • Susannah says:

    Pfffftt = are you serious ??? yawn…
    I could be considered “Maori”- what’s your point exactly ???

    if the use of this substance is not “responsible” now – HOW would further legal sanctions make it so….people break laws everyday.and will continue to, until the end of time …think about innocent young children- Who protects them????????????????

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