No, marijuana use doesn’t lower your IQ

No, marijuana use doesn’t lower your IQ

Several studies have come out that are debunking this claim that heavy marijuana use makes you dumber, which originates from a 2012 study.

A 2012 Duke University study made international headlines when it purported to find a link between heavy marijuana use and IQ decline among teenagers. Other researchers questioned the findings almost immediately: Columbia University's Carl Hart noted the very small sample of heavy users (38) in the study, leading him to question how generalizable the results were.

Then, a follow-up study published 6 months later in the same journal found that the Duke paper failed to account for a number of confounding factors: "Although it would be too strong to say that the results have been discredited, the methodology is flawed and the causal inference drawn from the results premature," it concluded.

Now, a new study out from the University College of London provides even stronger evidence that the Duke findings were flawed. The study draws on a considerably larger sample of adolescents than the Duke research - 2,612 children born in the Bristol area of the U.K. in 1991 and 1992. Researchers examined children's IQ scores at age 8 and again at age 15, and found "no relationship between cannabis use and lower IQ at age 15," when confounding factors - alcohol use, cigarette use, maternal education, and others - were taken into account. Even heavy marijuana use wasn't associated with IQ.

It is important to note that the researchers are testing this on children. I've been saying for a while now that the marijuana isn't a CAUSE of lower IQ or mental problems, but a symptom of it. Some people are more predisposed to seek out drug usage. That's just the way things are. But to make the jump that the drug is causing the behavior is ridiculous and requires MUCH more study to confirm.

While I still agree with the 21 year old minimum to partake (just in case), it is quite clear that we don't need to treat it like alcohol or tobacco when legalized. It's time to give marijuana its fair due. Legalize it!

I've never thought it lowered IQ, just memory function.

a reply to: KnightLight

I've always felt that the 21 year old requirement is a good check for under age buying. Many of age people will buy for people a few years younger than them, but someone many years younger is a bit more doubtful. So a 21 year old would be more likely to buy for an 18-20 year old, but not so much a 16 or 17 year old. Meanwhile if the legal age were 18, an 18 year old would be much more likely to buy for a 16 or 17 year old than a 21 year old.

In this way, I've always felt like the minimum drinking age should be more of a guideline or civil infraction then an arrestable offense.

I got a friend who was an avid user.. Let's just say he has become a little dull. (including depression etc.)
Not the same guy he was before. But maybe that differs from person to person.

It amazes me how people will go so far out of their way to try to find SOMETHING bad about marijuana. How about doing research on the good it does or take a poll on how people react while smoking it. I've been around marijuana my entire life and never once have I been beaten by someone who smokes it, or seen someone wreck a car while smoking it, nor have I seen anyone overdose on it. Legalizing marijuana would not only bring in more money but it would also stop a lot of "criminal" activity. So much more good comes from it than bad.

Great OP providing some tangible facts to allow people to form an opinion on this matter. For a lot of people who don't smoke marijuana this will ease some false fears and remove the stigma of the stoner getting more stupid by the puff.

However, having smoked this stuff for a long time I see the widespread use and accepted smoking of marijuana as dangerous. I understand not everyone will abuse it but in my experience and that of a lot of people I know smoking this stuff takes over your life. You cnt go to bed without a smoke, you cant get through a few hours without a joint. You cant have a night out without getting stoned and also cant have a relaxing night in without getting stoned. I personally felt I was very passive and lost all will to think or question things the way I used to.

What I am saying is that this has the potential and a huge one at that to pacify the masses. It takes the fight out of you and you literally couldn't be arsed standing up for your rights because you cant even be bothered to get off the sofa.

Ive eventually stopped which was very hard, but a lot of people I know can not get off this stuff. So be very careful about starting to smoke this stuff regularly.

My conspiracy conclusion: I see the more widespread acceptance of marijuana in the media with all the "celebs" openly encouraging it. The more studies are coming out and pointing to the positives. Some states and countries have begun to legalize and some do show benefits. However I just have this feeling that this is a play by the top players to neutralise the mass and get them to all grow dreadlocks.

a reply to: liteonit6969

I've heard that conspiracy angle before and frankly I don't agree with it. Clearly marijuana users are still passionate about things, since they are passionately arguing to legalize it. And have been doing that since 1996 when California became the first state to lax marijuana laws (legalized medical marijuana).

Also it sounds like you were addicted to marijuana. Addiction IS a possibility for users, as it is for all substances. But you know what would be better for you than what happened? If it were legal and you were able to freely pursue addiction recovery services without fear of reprisal or reprimand.

a reply to: PageLC14

Yes that is because everyone is so wasted to do anything. Put this scenario of a stoned mass where the government decide to take away some of those rights for example take away the guns. I can honestly say that it would be 100 times easier with minds pacified by marijuana than the usual alert mind which is the way we are made.

This is not a time to legalize any drugs, all it does is takes peoples minds and eyes off the sh*t that is happening and allows TPTB to do what they want and those big red eyes aint gonna pick up a thing.


But if miley cyrus and rihanna does it.....it must be fine.

f*ck this im away to get stoned....and watch xfactor reruns

Not sure why people seem to always assume that weed use is recreational. As a person who suffers from Crohn's disease, I can speak to how it's helped with my condition, making the pain levels more tolerable and helping me with eating, but hey, instead of harmless marijuana, why not just pump my body with drugs like Humira or Remicade instead...sigh...

Did I read that right?
8 year old heavy users?
How does a kid that young get pot or pay for it?
I didn't have any money when I was 10.

a reply to: Krazysh0t

I understand what you are saying and it is a long complicated argument against the pros and cons but all I can do is speak from my experience and that of around 30 odd people I know who smoke it. Yes I think I was addicted to it, but apparently it isn't addictive...hmm...in my opinion everything is addictive...as its down to the user.

It will make society a lot more calm, peaceful and remove the marginalisation of those who do use it for both medical and recreational purposes. But I just feel in todays current political climate and with the constant erosion of our rights and freedoms that people need to be more alert and aware of what is going on around them. Most people don't know whats going on and if they get some extra "relaxation" time they will never wake up and smell the coffee.

a reply to: intrptr

Life is all about chasing whatever addictions, they don't necessarily have to be substances either, we have. Even in AA, they have you just replace one addiction with another (they like to call it a hobby or a higher power). Fearing addiction is silly since it is rapidly becoming apparent that human behavior DEPENDS on addiction.

a reply to: liteonit6969

The alert and awareness that you speak of is causing people to succumb to their fears and let the media fear monger them. Many marijuana users claim that the plant expands your mind. Wouldn't it be better if everyone expanded their mind and learned how to think for themselves?

a reply to: Hoosierdaddy71

I'm pretty sure that the 8 year olds were picked as a control group so that the scientists could monitor their IQ change when they were 15 and heavily using.

a reply to: liteonit6969

Am I wrong in stating that you can not get addicted to marijuana? In the sense that if you were to stop it would cause withdrawals? in that case, if a person feels like it is over running their life they would be able to quit no problem. I have never met someone who has let it "take over their life." In fact, a majority of the people I know have great paying jobs that they have kept regardless of smoking. The only way to get to how you described is if you LET it get to that point. Which really goes for anything.

ETA: yes it causes relaxation, but let me tell you this, it DOES not effect the way you think or react. If someone were to try to take anything away from someone, regardless of whether they're high or not, and they don't want that thing to be taken from them, they will still be able to get up and fight for it. It doesn't cause impairment or make you change your beliefs.

a reply to: liteonit6969

guess it all depends. For me though I've never met a stoner who supported the government. Kind of makes you question things. I guess it's misguided of me to think everyone will be like my people always were and are, but do you know people who watch TV? Smoking made me allergic to commercials and "PROGRAMMING" haha..

If the conspiracy is to get people to smoke and be lazy, they're kind of waiting till the last minute and getting in their own way trying to spread marijuana.. It doesn't make any sense. Now adderall, alcohol, SSRIs, yea that makes a lot of sense..

Something that makes you go,
"wait.. does the news always sound like this?"
"whoa if they're lying about this, what else are they lying about."
"oh is programming a computer the same as using functions in math equations the same as controlling a population?"
BIOS.. Flash the BIOS.. BIOS in this case is obviously Biological Input Output System.


Power comes from participation.
Make up your own game because you get disillusioned from the main one.

originally posted by: PageLC14
a reply to: liteonit6969

Am I wrong in stating that you can not get addicted to marijuana? In the sense that if you were to stop it would cause withdrawals? in that case, if a person feels like it is over running their life they would be able to quit no problem. I have never met someone who has let it "take over their life." In fact, a majority of the people I know have great paying jobs that they have kept regardless of smoking. The only way to get to how you described is if you LET it get to that point. Which really goes for anything.

You can't get addicted physically, but there is belief you can mentally convince yourself you are in fact addicted...