Stoners Beware: NZ Study Finds That Regular Marijuana Use Causes Memory Loss, IQ Drop

Attention, stoners. Put down the enormous sandwich and listen to this one: an intensive study of more than 1000 New Zealanders has found that regular cannabis use can be linked to memory loss and even a drop in IQ, and academics from around the world have come out to back the study.

The study followed 1037 Kiwis born in 1972-1973 over the course of 27 years -- from a physical exam when they were 13-years old, right through to their late-30s and early-40s.

The study found that those who used cannabis in their teens and kept using it regularly through adolescence and into adulthood experienced cognitive memory impairment and decline by the time they were 38.

The researchers undertook an extensive background study to rule out any other factors influencing the results, and found data that indicated that the results were, in fact, accurate:

Poor education was ruled out as a contributing factor to lower cognitive function, as those who experienced poor marks in their studies due to cannabis use also included those who finished high school, and the effects of cannabis use found to be more severe in users who had a longer history with the drug.

Scientists also observed a "dose response relationship" between the use of cannabis and the decline in cognitive ability that could not be attributed to other factors like alcohol, tobacco and even schizophrenia.

Professor Wayne Hall with the University of Queensland Centre for Clinical research said of the study:

This prospective study greatly strengthens the case for regular cannabis use being a cause of cognitive decline by mid adulthood (age 38) in young people, especially who began to use cannabis in their teens and who persistently used throughout adolescence and into adulthood. Its findings add to the case for preventive public health education to reduce adolescent initiation and use of cannabis.

While Professor Robin Murray, a professor of psyhciatric research at Kings College London said:

“There are far fewer studies on its effect on minor psychiatric illness or on everyday life. However, there are a lot of clinical and educational anecdotal reports that cannabis users tend to be less successful in their educational achievement, marriages and occupations. It is of course part of folk-lore among young people that some heavy users of cannabis (my daughter callers them stoners) seem to gradually lose their abilities and end up achieving much less than one would have anticipated. This study provides one explanation as to why this might be the case.

Is this study going to make you put down the bong?

Image: Thor

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    Their memory and IQ might suck but boy are they're good on that Playstation! ;-)

      And isn't that what really matters? :D

    "Stoners Beware: NZ Study Finds That Regular Marijuana Use Causes Memory Loss, IQ Drop "
    Ummm.. Whaa.. No man I'm full.. Thank a bunch tho....

    Anyone who has watched a friend regularly indulge in high amounts over even a few months to a year can testify to this, I feel.

      Agreed. My stoner friends are dumber than they were. Nicer, but dumber.

    Regular enough use of just about any mind altering substance will have this effect. Including alcohol. But alcohol's okay, because it's legal and a huge part of our culture. Crazy.

      Don't forget the government can tax alcohol heavily, too!

      +1000. I'm a regular pot smoker and I accept the dangers to my health, memory and so on. However if I find it insane I could go to jail for casually enjoying a bong at home, while people get stupidly drunk and cause more damage and death (on a perfectly legal and socially accpetable drug) than all the illicit drugs combined.

        I've actually never tried any drug other than alcohol, illicit or otherwise. I respect the choices of others (perhaps not the ones that hurt themselves), but it's just not for me. But I just can't stand seeing the crazy double standards. And don't get me started on the impact marijuana knee-jerkery has had on what should be the hemp industry. An industry that deals with a substance that can't even BE smoked, and would have huge positive financial, economical and environmental effects if used instead of cotton.

    wait wait wait, hold up........why is there a capsicum pipe?

      Probably 'cause the bong broke. Resourceful bunch, stoners!

    "However, there are a lot of clinical and educational anecdotal reports that cannabis users tend to be less successful in their educational achievement, marriages and occupations."

    Get real. I work full time, i've got a girlfriend and a good career direction and I smoke regularly.

      I might add, these thoughts people have that stoners achieve nothing are just victim to propaganda.

        I'm the same, but boy can I tell you how tempted I get to throw in my job.

          I see none of you understand the concept of 'statistical significance'. Or the meaning of the word 'tendency'. That may be the effect of the dope.

        In other news, there are always outliers and not EVERYONE is affected the same way by stuff

        Not everyone to eats is obese, not everyone who drinks beer is an alcoholic, but obesity and alcoholism are both very real, and terrible problems.

        Anyone who is not being defensive about it and being honest, who has seen others use Marijuana in large amounts over a long period has seen them decline.Chances are good that heavy use isn't going to help you be the first person on Mars

          But they might *think* they're the first person on Mars.

          And in the end, isn't their hallucination as valid as our reality?

          Just saying ;-)

        Keep telling yourself that bro...

          If you're being sarcastic then you agree that 'stoners achieve nothing', in which case I would very much like to hear your definition of achievement.

          You obviously don't define achievement by someones monetary value or you would recognise Sir Richard Branson's success founding the multi billion dollar Virgin empire, you don't see Carl Sagan's contibutions to astrophysics and the larger scientific community as an achievement and you definitely don't recognise the 22 olympic medals won by Michael Phelps as achievement because "stoners achieve nothing" and each of these people smoke currently or were smoking weed during their years of success.

            I can name a whole lot more successful pot smokers if thoes three havn't achieved achieved enough for you

              +1 . You can add Steve Jobs and Lester Grinspoon to that list. And pretty much all the baby boomers of the 60s that actually had a sense of fun.

    I think it's important to note, that this study was conducted with young people who were regular users during their teens. As with any substance (prescription or otherwise) being taken during pre-adult years, it can have negative effect on brain/body development - from what I've read it takes until the early 20s for the brain to have fully matured.

    So while I do not think young people <20 should consider using Cannabis, the using of it by older people is a somewhat separate issue. I'd like to see an additional study with those who did not smoke until after the age of 21. Also, it must be noted that 1000 people in a very limited population to work with. While I'm not saying the research is wrong, further follow up studies need to be conducted to provide additional evidence.

    In either case, don't take substances unless you are prepared to wear the negative effects they can also yield.

      Yup, 100% in agreeance with ya there. I admit I am a user... probably average once a week. I don't touch alcohol and my diet and fitness regimes are superior to everybody I know. I am very health conscious. I shuold also mention that I am a science student at university. For me personally, I consider that the stress relief, sleep assistance, and mental clarity benefits outweigh the potential problems.... even if they don't... well I am still prepared to wear the negative effects and still be confident that in 20 years I will be in better stead in terms of my health and my career than most of my peers
      Also, why did they not include the exact figures in this article?? I would like to read the exact study myself and I couldn't see it in my brief search through the science article databases

        I was going to say the same thing. Why is there no source for this article? There are plenty of ways to make data appear differently. I want to see exactly how they created a control group because at the moment this looks suspiciously like some scientists measured some people's IQs against what the scientists THOUGHT the IQs should be.
        Please provide a source when it comes to 'studies.'

      The study found no evidence of similar problems affecting people who only took up cannabis as adults.

    what a waste of money. i could have told you that

    I have no issues with people smoking weed, but man, I have never met a bunch of people that act so high and mighty about their substance abuse more than stoners.

      Then why do you automatically call it "abuse" and not just "use"?

      What about drinkers? Tell them that they're abusing a substance and they'll tell you 'it's our culture maaaaaaaaaaaaaaaaaate'.

    What about occasional use? Does the study look at what constitutes 'regular use'?

    I didn't take up regular smoking of it until I was 21 - It's been over a full year and so far I have gotten a great job a place and way more sociable... If anything I have to thank it for relieving any stress and enjoying life that little bit extra. I also love no hangover ;).. I dunno but you be the judge.

    It improved my grades and comprehension of material, when I took up smoking.

    While some here may say they have it all sorted while being regular users - imagine what you could accomplish without having a substance dependency.

      no one here is saying they have a substance dependency, they are saying that they are fine in their life and smoke.

      Not all substances are used because people are dependent on them. Something to consider.

      I smoke because I want to smoke. Not because I NEED to.

      Is it addictive?

      I think anything that's nice has potential to be addictive to a number of people. But being addicted to the feeling is different than being addicted to the substance itself. There's an argument to be made here; "What's the difference between being addicted to the feeling/substance?" you might ask. Well, the difference is purely in how your body treats it on a physical/mental level. Yoink a stoners supply for years and he might have a bitch about not being able to smoke, but he won't dive into withdrawal mode because their bodies haven't become attached to the substance being put in.

      There are a few people out there that treat any and all substances like they can't go without. Hell, I've had co-workers that wouldn't do an ounce of work without their coffee fix. Shit goes too far from time to time. But if you're responsible heading into it and you know how to control whatever it is you like to do (be it a substance of some kind or a hobby) you'll be right as rain to continue filling those bowls/pipes/bongs/glasses/needles and pill bottles for as long as you see fit. Don't judge on the worst case scenario's or the popular opinion. Everyone treats everything differently.

      And it's by that logic that I disregard these type's of studies.

      Laughter produces chemical changes in the brain which affect mood and cognition. Imagine a world without laughter.

    No wasy duude!...No freakin waaay!...

    I smoke a tobacco pipe instead, keeps my brain alert. Love a good latakia blend.

    @BK It says that by the time your 38 it will have lowered your IQ. Since by you saying you began at 21 and its been a year, that makes you 22. Since 22 is a long way off 38 and your cant figure that out, then I would say it's already begun to impair your brain function.
    Think of it this way, in the short term there's not a very noticeable difference. If you saw someone every day or every week, then you wouldn't know the difference as it happened gradually over time. But if they moved away and you saw them 10 years later at a school reunion or whatever then you would have a WHOAH what happened to you moment.
    This study is about long term consequences, the 10-20-30 years of using "soft" drugs. Most people can see how bad the "hard" drugs are, they can ruin peoples lives very quickly, what this study is showing is that the "soft" drugs can also be bad for you.

      I get that, I do actually plan on phasing it back out as soon as I have some more responsibilities again, even drinking alcohol for that period of time can cause damage to your internal organs.
      I just believe as long as I use soft drugs in a safe environment in what I believe at appropriate times it shouldn't have as much negative effects as positive. Everyone is different - Most people I know that have been smokers stopped around the time of trying for kids and then never had the need to pick it back up again.

      Read it again. It says people who start using weed in their younger teens through to adulthood will have a decline in cognitive ability. The point is made that users who began smoking weed in their 20's are much, much less likely to experience the same decline in cognitive function.

    I started smoking regularly in grade 10 at school and I'm still smoking at age 28. I was Dux of my school, completed a PhD in theoretical physics (quantum field theory in curved space-time). I'm now running my own quantitative finance company and Im in a successful long term relationship. There are plenty of other people I went to uni with, who smoke regularly and are just as successful.

      good on you mate! I'm trying not to go there with the obvious curved space time joke...

    I used cannabis when I was working and building a prototype and that I later got a patent on that I won awards at MIT for it. It help me be more creative and after 45 years of partaking, its still how many are still damaged by Reefer Madness and the scam of Yellow journalism.

    Working fulltime, have a fiance and 3yo together. Been smoking since around 16, and in my job interview we had an iq test of which I got the best result..... Maybe they were "stoners" too?

    I think I have heard about this before... but I can't remember where or when....

    What is with Luke and the anti-drug articles?

    Is this the same type of research where they literally smoked out chimps until they died due to suffocation?
    There are so many factors to these kinds of studies that just can't be equated.

    Plenty of evidence out there as well of the overwhelming medicinal benefits of cannabis.

    Lets not forget that there are ZERO deaths associated with cannabis use.
    How many are there for prescription drugs and alcohol?
    Oh right... Tens of thousands and into the hundreds of thousands.

      Don't tell Luke that, all drugs are evil to him.

    It’s a really interesting study - I've also been a regular smoker for most of my adult life (i'm 36 right now). I've always been ahead of the curve when it comes to achievements, measured both in terms of salary and personal happiness. I've recently sold my company and have earned above $300k a year for the last several years. I have recently celebrated 11 years with my partner, we have 2 children, 9 and 5. I smoke weed every night, usually when the wife and kids have gone to bed (she still gives me shit though). I have a nice 2 hour period from 9.30pm to 11.30pm where I can relax and get a bit stoned. What I find really helps is the internal dialogue that I have with myself. I replay the events of the day and relive them from a slightly different perspective. I find this process really valuable and have gained much insight from it. What I will say to other weed smokers is this. Don't let it define you or take over your life, smoke for fun and use it as a positive tool for social interaction or personal achievements. Keep your brain active, challenge yourself, benchmark yourself against your peers regularly. Each year take a month or two off from smoking and see what the changes are. Then look forward to that first bong after the break! (and ensure you are home alone when you do because you and that couch will become very good friends for the afternoon)

      +1 very very well said

    All New Zealanders have low IQ's. That's just them.

    All those people regaling their successes while still being smokers, have you ever stopped to think that by the content of the sites your commenting on, you aren't among the usual stoner demographic? I know, I know "What is the usual demographic then?" and other defenses. You all know what I mean and in this case, I'm actually saying you are the outliers not the norm so don't take it personally.

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