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Twins Study Finds No Evidence That Marijuana Lowers IQ In Teens (sciencemag.org)
sciencehabit writes: Roughly half of Americans use marijuana at some point in their lives, and many start as teenagers. Although some studies suggest the drug could harm the maturing adolescent brain, the true risk is controversial. Now, in the first study of its kind (abstract), scientists have analyzed long-term marijuana use in teens, comparing IQ changes in twin siblings who either used or abstained from marijuana for 10 years. After taking environmental factors into account, the scientists found no measurable link between marijuana use and lower IQ.
That isn't how twin studies usually work. In this case, one twin decided to smoke marijuana, while the other did not. They weren't assigned roles in an experiment by researchers. Their parents either didn't have a problem with the drug, or they weren't involved in the decision.
It was likely survey based. I.e. they found identical twins and asked them if one used and one didn't, and if so, they evaluated them afterwards.
Anyways I'm kind of disappointed that they only looked at IQ, as to me it's a meaningless figure whose only purpose is for "I am more smug than thou art" clubs like Mensa. I'm more curious about other functional measurements both physiologically and sociologically (i.e. how did they vary in terms of career success.) There's some evidence that marijuana can improve both, as well as evidence that it can harm both.
I knew many very smart people who did marijuana. I would have thought most of them would have done more with their smarts but I see them now and they're mostly just getting by. They are happy for the most part though. Thinking about it I'm not sure if it's such a bad thing.
You didn't read TFA. The study is of teenage twins who previously had/hadn't smoked marijuana (ie they were given questionaires, and twins were then selected for IQ testing if one had smoked and the other hadn't) not of twins who signed up to take part in a controlled experiment.
Parents either had nothing to do with it, or simply failed to prevent one of their twins taking the drug.
The study is probably, to a certain extent, flawed because of that methodology, but without commiting ethics violations of the type you describe, there's probably no way to get a more accurate result.
You are not alone. This is not normal. None of this is normal.
The people in Flint, Michigan are about to gain a first hand appreciation of what lead does to cognitive abilities.
I am Slashdot. Are you Slashdot as well?
You are correct
From the study
Standardized measures of intelligence were administered at ages 9–12 y, before marijuana involvement, and again at ages 17–20 y. Marijuana use was self-reported at the time of each cognitive assessment as well as during the intervening period. Marijuana users had lower test scores relative to nonusers and showed a significant decline in crystallized intelligence between preadolescence and late adolescence. However, there was no evidence of a dose–response relationship between frequency of use and intelligence quotient (IQ) change.
Very smart people are not always very motivated people. And vice versa.
Take politics as an example.
There are two types of people in the world: Those who crave closure
And if drugs policy is to be based on facts then this sort of fact is just one more reason to give it up already and let adults decide what plants they'd like to benefit from.
Indeed. There is a real problem when the biggest detriment that people can identify for using an illegal drug is the very fact that it's illlegal. When the primary concern isn't that the drug will kill you, put you in the hospital, give you organ damage, make you crazy, or make you dependent upon it, but is instead that you'll be fined or tossed into jail, something has gone horribly wrong.
When you have people taking 'bath salts' instead of cocaine, which has a much higher chance of, I don't know, chewing somebody's face off, because the latter is illegal as well as the former, but the 'bath salts' are more accessable for those that would use drugs, we have a problem.
I don't read AC A human right
The "safety" argument relative to drug legalization is huge red herring designed to drag legalization proponents down the path of needing to claim that marijuana is safer than tap water, or worse, into wild and unproven claims of its medical benefits.
The results of marijuana's relative safety have been in for years -- you can't really overdose on it and decades of mass use have failed to show any significant signs of problems in the general population. This is more than we can say about alcohol, acetaminophen, anti-depressants and whole long laundry list of substances that are legal and easy to get.
The REAL argument is that the public policy of marijuana criminalization has been an abject failure. We've spent trillions of dollars on prohibition on it and all we have to show for it is a complete dismantling of our constitutional rights, corruption of a law enforcement system that has produced an epidemic of civil rights abuses quite often enabled by the elusive pursuit of marijuana users (you didn't think they wanted to stop you for a traffic offense, did you?), an erosion in public respect for laws, almost certainly a disregard for the graver risks posed by other illegal drugs, and a criminal justice system that has ruined thousands of lives and built massive criminal enterprises
What we don't have to show for it is any reduction in marijuana use or availability. As a matter of public policy it has failed in its goals and produced a plague of horrific side effects.
This is the argument that needs to be made. The safety issue is a total and complete distraction.
I live in the Netherlands, and we've had easy access to cannabis for a long time now. When I studied, a lot of roommates smoked it sometimes, and the heavy users had a few plants in their room. About a quarter of the teenagers have used it incidentally, the rest doesn't really bother with it.
With the experience we have locally we have also seen some issues. The issues are mainly psychological issues - IQ drops haven't been seen but motivation does tend to suffer from long term use. There is a very real link with schizophrenic disorders but it's unknown if people who have the genetic predisposition smoke cannabis because of that, or vice versa - in any case, if you have schizophrenic disorders in the family it is very unwise to smoke cannabis long term, although short term and incidental use may be safe.
Also, an acute psychosis brought on by too much cannabis is a well-known issue and cause of death for young tourists in Amsterdam as well. Usually we have a few casualties each summer because people in a psychosis sometimes think they can fly.
For the majority of incidental users, cannabis is MUCH safer than alcohol. However, there is a minority with genetic vulnerability to cannabis that should not use it at all, and long term use of cannabis (2+ years) is probably unhealthy for a much larger group - and I'm ignoring the wider and well-known effects of smoking here, since you could also drink it (as thee) or eat it (in cake).
I'm not against recreative drug use. It should be decriminalized asap. But it's not as harmless as some people make it out to be, even if it doesn't do nearly as much damage as alcohol or cigarettes.
Therefore, by the (faulty) logic you're using, you're just a cow with a keyboard - osu-neko (2604)
No, most of us aren't familiar with your anecdotes.
You posted an comment so vague it is meaningless. You did not provide anything agreeing with or refuting what was written.
There's nothing to agree with or refute. If you take even a cursory look at the story, you will see that this was not the kind of study that the GP assumed it was.
Teenagers were not subjected to drug use for this study. Adults who had used marijuana as teens were studied.
The first hint was right there in the summary:
If we're studying the effects of marijuana use on teens, and ten fucking years have gone by, then what exactly is the probability that these subjects are still teens at the time of the study?
Go ahead, get out your calculator and I'll wait here for your answer.
You are welcome on my lawn.
It's a sad comment on our society where we are so worried that there might be some natural substance that makes people feel good that before an effective drug can be approved the feel-good properties have to be removed.
You are welcome on my lawn.