Study: Teen Cannabis Users Have Poor Long-Term Memory in Adulthood
feinberg.northwestern.edu
feinberg.northwestern.edu
For people who have access, I highly recommend this review article from June 2014 in the New England Journal of Medicine, arguably the most respected scientific medical publication in the world, which goes over the published scientific litterature about Marijuana: bottom line, it's not as innofensive as some make it to be, and adolescents are most at risk. Caveat Emptor.
http://www.nejm.org/doi/full/10.1056/NEJMra1402309
(personally, I do believe it should be legalized for policy and social reasons, but that doesn't mean I think it's biologically harmless)
I don't believe anyone is claiming that MJ is harmless; but that overall, MJ's harm is lesser than the harm caused by alcohol or tobacco. Teens are already known to be more susceptible to chemical substances because of their developing brains, so this study doesn't seem to be very surprising.
(We should end cannabis prohibition, and are obviously in the process of doing that, but I'm having no trouble turning up tons of recent cannabis research studies.)
Why would cannabis be less harmful than tobacco? The smoke from each is roughly the same, with the obvious differences being nicotine in tobacco and cannbinoids in cannabis.
Maybe cannabis smokers smoke less frequently than cigarette smokers; but maybe they inhale the smoke deeper and hold it longer.
It's a bit frustrating that anyone who expresses any concern about cannabis is written off as a propagandist of an oppressive government.
(I'm pro legalisation)
The comparison I've heard is that a regularly smoking 1 joint a day is roughly equivalent to smoking 1 self-rolled cigarette using tobacco grown without additives.
Correct. Unless you include users who mix in other substances to increase the efficacy of the cannabis they are smoking.
I've had friends mix everything from coke, meth, crushed barbiturates and yes even tobacco in with their cannabis.
They're mixing coke and meth in to smoke coke and meth.
But unlike tobacco, cannabis does not contain a chemical as highly addictive as nicotine. Your average tobacco smoker probably smokes an order of magnitude more tobacco than your average cannabis smoker smokes cannabis. Evidently there is a nonzero risk of physical or psychological dependency for marijuana, but it's nowhere near the risk profile of tobacco.
> Smoke for smoke, cannabis and tobacco are probably
> equally harmful.
If you smoke heavily from 14 and quit at 18, your health risks from tobacco will normalise to that of a non-smoker after x years, but there's a suggestion here that if it's cannabis you're smoking, you've caused yourself irreparable harm
The smoke itself is made up of polycyclic aromatic hydrocarbons like anthracene. These molecules are carcinogenic on their own, and activate the bodies' inflammation response causing additional damage. In this regard, both marijuana and tobacco will have very similar detrimental effects. However, some of the compounds found in marijuana, like cannabidiol, are anti-inflammatory agents (targeting the CB2 receptor), which helps prevent some of the damage that would otherwise be caused by the smoke (but not all of it).
The other source of damage is radioisotopes absorbed from the soil. The tobacco plant tends to absorb radioactive elements like polonium more readily than many other plants. These radioisotopes are deposited on the lining of the lungs, where they undergo decay, causing cellular damage. Marijuana may or may not be similar to tobacco in this respect, but I have not done much research on that.
This isn't going to be a significant issue if it's grown indoors. Also, a large part of the reason why tobacco has a lot of radiation is because of the fertilizer that sticks to the leaves, whereas this isn't an issue with cannabis because it's not being fertilized by crop dusters.
I'm guessing it's probably because you don't have to smoke as much as tobacco.
Also, anecdotally: I have yet to hear of someone getting lung cancer from smoking pot. Heck, Willie Nelson has been toking up for decades, and apparently his lungs are just fine.
And then there's this: http://www.cancer.gov/cancertopics/pdq/cam/cannabis/healthpr...
> It's a bit frustrating that anyone who expresses any concern about cannabis is written off as a propagandist of an oppressive government.
That was not needed.
http://www.m.webmd.com/a-to-z-guides/news/20060523/pot-smoki...
http://www.enewspf.com/latest-news/health-and-fitness/53910-...
But, Barack Obama was in the "Choom Gang" when he was in high school, which roughly translates to the "Marijuana Gang". Think about that: The current leader of the free world smoked so much as a teenager that he and his friends named their group after the drug itself.
The last three US presidents have said that they smoked marijuana as teenagers and college students. Carl Sagan was a big proponent, and there are many other successful people in the worlds of politics, science and business who smoked pot casually at the least. If it does change the structure of the brain and impair long term memory, what exactly does that mean? Whatever the effect, it apparently doesn't disqualify people from being among the most intelligent and successful in the world.
Brain studies are useful, but we should be cautious when using them to draw sweeping conclusions about social policy.
Wonderful. Another study with no basis for distinguishing causality from correlation.
I bet you can randomly select a subgroup of 18-percent poorer performers and find that they have all sorts of things in common, from diet to exercise to presence or absence of parents - as well as bizarre factors like who was born on a Tuesday.
There are probably dozens of markers that both correlate with these kinds of results and also plausibly suggest an explanation.
> “It is possible that the abnormal brain structures reveal a pre-existing vulnerability to marijuana abuse,” Smith said. “But evidence that the longer the participants were abusing marijuana, the greater the differences in hippocampus shape suggests marijuana may be the cause.”
What?! No it doesn't. It suggests quite the opposite: that people with greater abnormality tend to use marijuana longer.
I suspect that, now that medical cannabis is widely available and somewhat widely used in the treatment of childhood maladies, we may begin to see, in the next decade or so, results based on much sounder science simply because of the availability of higher quality sample groups.
This study however does not stand by itself. There will be more, if there aren't already, and all they are doing is backing up the conventional wisdom about the effects of marijuana.
It definitely makes you forget. I grew up with two parents who smoked it, DAILY. They remembered nothing. Seriously.
However, I think that studies like this are particularly vulnerable to this critique of methodology. Any time you assess the performance of a large group and then divide that group into subgroups, you are going to find trends of varying levels of statistical significance.
It is incredibly easy to do. http://www.tylervigen.com/
That is why, in every scope-and-methods class in every college across the country, the various methods for ascertaining causality are demonstrated and taught.
Reading only the linked article and not the study itself, I so far have the impression that none of these were seriously considered - presumably on the basis of ethical treatment of humans subjects. You can't just take a group of people with a particular set of desirable control features (perhaps, in this case, a typically shaped hippocampus) and force-feed them cannabis smoke for three years.
On the other hand, it's just as easy to read this study as meaning that people who performed poorly on the relatively specific requirements of this study seemed to prefer to smoke marijuana. If this study were about serious science, the conclusion might be the utterly uninteresting sky-is-blue headline, "absent-minded people likely to smoke weed."
user has made no other comments thus far.
In the absence of a randomized trial, the dose-response relationship is one of the most important tools available for teasing out causality. If you can't show that increased dose strongly correlates with increased response, you likely are looking at population variables, not drug/lifestyle effects.
It turns out that almost everything that gets people's hands wringing from fatty foods to chemicals with complicated names have almost flat dose-response curves. The ones that stand out as having strong dose-response curves are alcohol and especially smoking, which meets all of the causal criteria you want to see in a correlative relationship: http://www.skepticalraptor.com/skepticalraptorblog.php/corre...
"Binging Alcohol Abuse Leads To Loss Of Working Memory In Teens": http://www.medicalnewstoday.com/articles/231267.php
No safe blood lead level has been identified.
-- http://www.cdc.gov/biomonitoring/Lead_FactSheet.html
Which, tangentially, reminds me of "Unsafe at any Speed"
Medicines all have a "therapeutic index", however narrow it may be. Poisons may not — and often don't.
He said "the difference between a medicine and poison".
Not between "poison and a medicine".
There isn't even an attempt to establish any sort of causality here yet the article uses the word 'affects'.
Correlation, sure, but correlation with length of usage. Definitely a more interesting angle than simply usage <-> deformation.
In practice it's nearly impossible to get the approvals you need.
(Also, in what way is cannabis worse on paper than methamphetamine?)
Pot is Schedule I, indicating no medical use and strictly prohibited.
- This study is self-serving for people who are anti-marijuana or
- Hacker News users tend to be interested in or users of marijuana and find this study concerning
I'd guess a bit of both but more the latter since the Hacker News community tends to be quite liberal.
44 healthy controls, 10 subjects with a CUD history, 28 schizophrenia subjects with no history of substance use disorders, and 15 schizophrenia subjects with a CUD history
http://schizophreniabulletin.oxfordjournals.org/content/40/2...
I'm no scientist, but it seems a little presumptuous to me to say I've come to a general conclusion about anything when all I have to investigate are 25 people. To quote the above "10 subjects with a CUD (Cannabis Use Disorder) history,... and 15 schizophrenia subjects with a CUD history".
After a brief Google search I found other studies where this same doctor (John Csernansky, MD) has linked marijuana use to "Schizophrenia-like Brain Changes".
This guy has over the course of several years come up with very damaging evidence that marijuana is irreversibly harmful to humans. To start with, to know who these studies are funded by would be helpful so I can know whether it deserves my attention.
If a person is injured in any way due to their consumption of alcohol (wreck, twisting an ankle, liver damage) they should likely have to foot the bill.
Fixed it for you. ;-)