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The Best Science Writing Online 2012
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Although teen smoking rates are at a record low, more of them are smoking pot and fewer than ever believe it is bad for them. Data released last December as part of the National Institute on Drug Abuse's Monitoring the Future project show that only 44.1 percent of 12th graders believe regular marijuana use is harmful, the lowest level since 1973. That may explain why more than one third of high school seniors tried pot in 2012, and one in 15 smoked it daily.
The growing acceptance of medical marijuana may be behind teens' changing attitudes. Since 1996, 18 states, plus the District of Columbia, have made it legal for adults to obtain pot with a doctor's prescription. And last November, Colorado and Washington became the first states to legalize marijuana for anyone older than 21 years. “This shift in perceived risk may very well have resulted from the widespread endorsement of medical marijuana use,” says Lloyd Johnston of the University of Michigan, who led the Monitoring the Future project.
But pot poses a higher risk for teens than for adults. In August investigators at Duke University and other institutions published the results of a 25-year study suggesting that heavy use among adolescents can do permanent cognitive damage. Subjects who were diagnosed with marijuana dependence as teens and adults suffered IQ declines of up to eight points between the ages of 13 and 38, even after the researchers controlled for other drug dependence, schizophrenia and education. (Abstainers' IQs rose slightly.) Moreover, the IQs of teen users did not recover even if they quit in adulthood.
How much marijuana is too much? “It's hard to find out,” says lead study author and Duke clinical psychologist Madeline Meier. There is no accurate way to measure consumption because marijuana joints are rarely identical and potency varies. What is clear is that adolescent brains are particularly vulnerable to marijuana's effects, so teens would be smart to abstain—and may stay smarter for it, too.
This article was originally published with the title No Harm Done?.
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17 Comments
Add CommentThe prominantly espoused connection with medical marijuana is completely unsupported. What consitutes "marijuana dependence", since physically there is no such thing? What is the mean, average, standard deviation, and margin of error on the "up to eight point" decline in IQ? How does this compare with alcohol abuse over a similar timespan? This article reeks of Reefer Madness, instead of the rational scientific results I expect from a magazine of your caliber.
Reply | Report Abuse | Link to thisLet's see ... when I was in high school, I tried all sorts of drugs: tobacco, alcohol, marijuana, ecstasy, GHB, LSD, psilocybin, etc. I graduated with a 3.0. 10 years after high school I went to college, and graduated 4 years later with a 3.9. The connection with a decline in IQ may be associated with the lack of brain-intensive jobs that allow people to have marijuana in their system. Use it or lose it. This study does not seem to account for the rise in intelligent programmers who smoke on a daily basis but work for themselves because no employer would hire them.
Reply | Report Abuse | Link to thisAgreed kbbpll.
Reply | Report Abuse | Link to thisWhy isn't the study linked in the article, or described in detail?
This is what I found. (You're welcome Scientific American)
"The study included information on more than 1,000 people born in New Zealand in 1972-1973. Participants took IQ and other mental functioning tests at age 13 -- before any had started smoking marijuana -- and then again at age 38."
"Marijuana dependence is defined as someone who feels they need to smoke more and more marijuana to get the same effect, who has tried to quit but can't or who keeps using even though the habit is causing them problems, such as with their health, family, work or school."
I'm interested in this little thing called CAUSALITY. What is the proposed mechanism through which marijuana stunts development? How do you know kids with a lower IQ aren't just more likely to smoke/become dependent on marijuana?
Love seeing science manipulated by moms to try to tell kids what to do.
I'm sorry. Could you please repeat the question?
Reply | Report Abuse | Link to thisThere is no better impediment to credible (anti) drug education than the double standards surrounding alcohol.
Reply | Report Abuse | Link to thisBy ANY standard of evidence (and there is little that validates the cannabis/IQ interpretation made from the NZ study, largely deduced from small numbers and conflated by the reports own data source where 80% of youth have tried cannabis >5 times and have come to no apparent harm). But 'causation' has not been established whereas for alcohol and IQ it has... suggests the researchers may have had a mother who liked her 1st trimester tipple.
Teenage brains are 'more' resiliant than adults. And risk taking necessary for maturity. Some applied science might benefit the researchers.... expand their narrow view of the world and add something to the academic storehouse than make stuff up. The also highly respected longtitudinal & multidiciplinary study (Christchurch) found that any aberation to mental health that resulted from cannabis use was to 1% of 1% of cannabis consumers and then ONLY measurable in laboratory type conditions (that is, unable to be replicated outside of controlled and conditioned testing) due to the subtle nature of the effects and that it is indistinguishable from 'life', factors that variously affect all of us anyway. And that is before we consider, on balance, how light, moderate and heavy pot consumption may be displacing other harms from legal intoxicants. Or how the harms that acrue from prohibitions unintended consequences directly and indirectly harm the mental health of those who do 'pot' and those who do not and are otherwise innocent bystanders in the disfunction the rules create.
I believe smoking pot is less risky for teens than many other things teens do, like smoking tobacco, drinking alcohol, or unprotected sex. I do agree that 21 should be the legal getting high age, but teens are always going to be bad and do things they are not allowed to do. I would rather they smoke pot instead of getting drunk, doing other hardcore drugs, or vandalizing stuff.
Reply | Report Abuse | Link to thisThey're placing way too much emphasis on IQ, as if it were important the older you get. A person who works in fast food, at Walmart, or as a receptionist does not need to continually keep getting smarter. All they need to do is preserve the functionality they currently have (even in the presence of dementia or Alzheimer's). Career advancement is not as important as people make it out to be; just live life, simply.
Reply | Report Abuse | Link to thisIndeed vapur, high IQ is quite often associated with other social deficits, loneliness being one that reappears often amongst the cohort. Until high IQ folk come to terms with their 'advantages' and see that social skills and other attributes maketh the man - their gift is pretty much useless. Which may well account for the reason IQ is found to be some points below what is expected in the study.... who needs it to be a better person. They have well have been measuring religious affiliation. "Smoking Pot decreases Catholic sentiment" at least would have universal buy in! Some might suggest Cannabis should be compulsory.
Reply | Report Abuse | Link to thisAlcohol & tobacho are no good for the health.
Reply | Report Abuse | Link to thisIt is just plain stupid to think that because pot may be no worse. That it is Ok!
This is pure adolescent thinking and we need maturity not immaturity !!!
Why add more drugs to the problem instead of reducing the problem.
The definition for the 'Intelligence Quotient' is the ability to learn. Relative to time.
Reply | Report Abuse | Link to thisHaving a high IQ doesn't make you smart. How you use it determines that.
I have met many intelligent idiots in my 69 years.
Because the mothers made the choice of getting pregnant for their own pleasure and bringing another person into the world.
Reply | Report Abuse | Link to thisThey are responsible for their choices and all the suffering of their offspring.
Having children is NOT A RIGHT BUT AN RESPONSIBILITY.!!!
Yea! Maybe he needs another joint !!
Reply | Report Abuse | Link to thisOf course none of this deals with the real issue, which is how we can mitigate the very real damage that the mis-use of psychoactive drugs can cause to individuals, families, and society in general.
Reply | Report Abuse | Link to thisThis fact is absolutely clear: A substance or activity that creates a sense of profound pleasure will be used, regardless of the law, and some people will get into trouble through over use or addiction. Others will not.
The question is not so much how various drugs compare in relative potential for abuse or danger, it is how to minimize that danger for all.
The most promising approach seems to be to treat this as a public health problem rather than a legal one. Create a system of "controlled availability" where psychoactive, potentially addictive drugs (including the currently illegal drugs, alcohol, and nicotine) can be purchased by adults for personal use through government controlled outlets. Couple this with ready access to education, counseling, and treatment funded by the taxes charged on the drugs.
The addition of a low key, subtle tax funded national campaign to remove the "glamor" surrounding the use of drugs; make it culturally "un-cool" might help to truly turn the tide. All this would cost far, far less than the current, totally failed, "war on drugs".
Agreed, rdevaughn. If marijuana causes stupidity, whomever allowed this article to be published must be stoned out of their gourds. Editors take note - I once cancelled my subscription because of similar stupidity. I'm going to give you the benefit of the doubt this time and presume that this was one massive brain fart on your part. Don't let it happen again. Your readers expect SCIENCE, not propaganda.
Reply | Report Abuse | Link to thisAnd I, many idiots who profess to be intelligent.
Reply | Report Abuse | Link to this> Why add more drugs to the problem instead of reducing the problem.
Who exactly, is adding more drugs ?
With Cannabis at the prevalence it is now, it may as well be compulsory.
For if I (or anyone else) was to market Cannabis and get more penetration, certainly more successful than the black market which by default you are endorsing, Coca-Cola or McDonalds would be vying for my 'expertise' along with a commensurate (profit share) paycheck.
Are you suggesting 'redoubling our efforts' will solve the problem? Or is 'more of the same, and expecting a different result' an indication of your claim to both IQ and intelligence?
How exactly does the prevalence and use of some drugs (legal ones) with known and quantifiable harms curry favour with you over the use of Cannabis, that on any reasonable scale can be said of "the harms are largely overstated" and how displacement of the former by the later DOES NOT result a net reduction in expense, consequence and burden on society?
How might I convince the sceptics that it not your intention, naively or purposefully to drive people to drink?
Just keen to clear this small philosophical matter up?
irrelevant nonsense.
Reply | Report Abuse | Link to thisI'm hoping, as a reader of SciAm, that you know better than to think that citing anecdotal evidence is relevant.
Reply | Report Abuse | Link to thisThough, your comment also shows you don't really understand basic statistics and how studies work.