12 ms·

Cannabis reverses aging processes in the brain

189 points by brahmwg 9y ago

simonsarris 9y ago
I'm not sure its wise to say "Cannabis" as a shorthand for "Low doses of THC." The headline of the paper is: "A chronic low dose of Δ9-tetrahydrocannabinol (THC) restores cognitive function in old mice. https://www.nature.com/nm/journal/v23/n6/full/nm.4311.html" https://www.nature.com/nm/journal/v23/n6/full/nm.4311.html" Which is interesting, but you shouldn't take it to mean smoking is good for your brain. We already have some data to suggest that smoking cannabis, at least while young, is linked to cognitive decline. "Persistent cannabis users show neuropsychological decline from childhood to midlife" (2012) http://m.pnas.org/content/109/40/E2657.full http://m.pnas.org/content/109/40/E2657.full
- justboxing 9y ago
  From the 2nd Link: > Persistent cannabis use was associated with neuropsychological decline broadly across domains of functioning, even after controlling for years of education. Informants also reported noticing more cognitive problems for persistent cannabis users. Impairment was concentrated among adolescent-onset cannabis users, with more persistent use associated with greater decline. Further, cessation of cannabis use did not fully restore neuropsychological functioning among adolescent-onset cannabis users. Does the last sentence mean what I think it means. That even after stopping cannabis use, the neuropsychological damage / cognitive problems remained, and didn't rollback the decline from cannabis use? If yes, it's troubling. All my stoner friends claim no permanent damage from chronic use
  - nerflad 9y ago
    Troubling, but not at all surprising
  - simonsarris 9y ago
    > If yes, it's troubling. All my stoner friends claim no permanent damage from chronic use I mean, your stoner friends have got to be making a strange claim in the first place. There is no magic Twin Earth, where yoga is a contact sport, John McCain is president, and they never smoked, that they can compare themselves to. We all decline somewhat from other factors, the question is just how much is attributable to what. How would they even be able to parse out their cannabis-decline from their age-decline, or from their haven't-practiced-long-division-recently decline, etc? If they are only thinking "I felt dumber when smoking but now that I stopped, it seems gone", well, that's something, but it can't be a complete picture vs their never-smoked potential.
    - kgwxd 9y ago
      "There is no magic Twin Earth" That's just, like, your opinion man. If they smoke enough, they've probably been to Twin Earth.
      - TeMPOraL 9y ago
        They've probably been to many places. http://slatestarcodex.com/2015/04/21/universal-love-said-the-cactus-person/ http://slatestarcodex.com/2015/04/21/universal-love-said-the...
    - exabrial 9y ago
      Acroyoga: https://en.wikipedia.org/wiki/Acroyoga https://en.wikipedia.org/wiki/Acroyoga Does that count as full contact?
    - babyrainbow 9y ago
      I have this same thought when people say their didn't have any problems even after they got all the vaccine shots as a child, so it is completely safe... How did you compare you with your version who never had shots? Or how did any vaccination trials do it?
      - roywiggins 9y ago
        You compare populations. Did a group who got the vaccine have more problems than an otherwise identical group that didn't? This requires careful study design and statistical analysis, of course.
        babyrainbow 9y ago
        > who got the vaccine have more problems than an otherwise identical group that didn't? But we were not talking about problems. The person I was replying said this > but it can't be a complete picture vs their never-smoked potential. So I am talking about the potential (meaning various capabilities IQ, Social behaviour, Emotional stability (withing the bound of normalcy) etc. I mean, things that are not usually recognized as problems..). How can you compare the potential of a version of you who never had vaccines with a version of you who had a given set of vaccines. This is particularly relevant with vaccines because you don't have a version of you before having vaccines, since these are usually administrated at a very young age..
  - PhasmaFelis 9y ago
    I thought it was well-known that marijuana use among adolescents was a risk factor for schizophrenia. I'm 100% for legalization, but no drug is ever completely safe. I had to talk a friend down from a nasty paranoid dissociation episode after she ate the recommended dose of a mass-produced legal pot cookie in Seattle. It's a hell of a lot safer than alcohol, IMO, but that's not the same thing as "safe".
    - Hydraulix989 9y ago
      Yes, I've had friends who've had similar experiences after ingesting edibles. Yes, there is some element of responsibility when it comes to consumption (nothing in life is risk-free), but it's not to the point where it should be considered illegal, to say nothing of the ruined lives caused by having a bunch of non-violent offenders run through our judicial system because they "got high."
      - PhasmaFelis 9y ago
        Absolutely. The best solution in my mind is legalization and education. That's why it pisses me off when people spread the story that it's 100% harmless--you can't be a responsible user if you don't know the facts, positive and negative.
    - whiddershins 9y ago
      I think it is psychotic breaks you could be referring to. Schizophrenia is its own thing.
      - PhasmaFelis 9y ago
        The studies I've seen connect schizophrenia with marijuana use in young people. My friend's episode may be something else; it hasn't recurred despite ongoing occasional use, and she hasn't shown any other signs of schizophrenia that I'd recognize.
    - gehwartzen 9y ago
      Kind of a side thought but we have kind of a strange cultural definition of what constitutes a drug. There are plenty of common foods which have physiological and neurological affects.
  - justifier 9y ago
    here is an illuminating issue with the trend of specifying interest as a science develops it usually branches into specific categories of study these categories and their proponents usually create language to simplify intercommunication of ideas but the issue becomes these placeholder words can sometimes be misunderstood: two parties each agreeing on a conclusion but holding different definitions for linking jargon; or sometimes are oversimplifications of their underlying ideas that are less interesting to the science being discussed what does neuropsychological mean? googs will tell you: the study of the relationship between behavior, emotion, and cognition on the one hand, and brain function on the other. wiki(o) will tell you: Neuropsychology studies the structure and function of the brain as they relate to specific psychological processes and behaviours so what is declining? the structure of the brain? how do you measure that? less neurons? less connections? do we know how many neurons or connections is ideal? or is behaviour and emotion declining? how do you determine desirability of emotion and behaviour? wiki also suggests methods of measuring this: https://en.wikipedia.org/wiki/Neuropsychology#Methods_and_tools https://en.wikipedia.org/wiki/Neuropsychology#Methods_and_to... ; which include card sorting(i) and brain scans the former suffering from what i would consider a fallacy of overfitting and the latter currently under scrutiny for overassuming(ii) it's also a young enough field that hn's spellchecker flags neuropsychology as a misspelled word.. perhaps the spellchecker's neuropsychology has been damaged do i care one way or the other on the short and long term damage from cannabis smoking? of course i am interested in the results but i hope in the future the language, from both sides, will become more descriptive and less inflammatory that said, much like with alcohol use, you are intentionally poisoning yourself in order to alter your perception of shared reality.. accelerated entropy should be expected but the more descriptive information we can form will better inform our decisions on whether the benefits outweigh the negatives (o) https://en.wikipedia.org/wiki/Neuropsychology https://en.wikipedia.org/wiki/Neuropsychology (i) https://en.wikipedia.org/wiki/Wisconsin_Card_Sorting_Test https://en.wikipedia.org/wiki/Wisconsin_Card_Sorting_Test (ii) https://www.theguardian.com/science/neurophilosophy/2015/apr/09/bold-assumptions-fmri https://www.theguardian.com/science/neurophilosophy/2015/apr...
    - Nav_Panel 9y ago
      > that said, much like with alcohol use, you are intentionally poisoning yourself in order to alter your perception of shared reality.. accelerated entropy should be expected This is an odd statement. Weed isn't exactly toxic like alcohol is. It's nearly impossible to overdose, any acute harm will be purely psychological (even though this thread is debating whether long-term harm can enter the physical realm). Also, we do all sorts of stuff all the time to alter our perception of reality, mostly not involving substances...
  - deleted 9y ago
    [deleted]
  - geoelectric 9y ago
    Well, if you read the results what it basically says is that if you started regular use from adolescence there was a clear IQ decline correlated in proportion with "waves" of diagnoses (iow, they measured a number of times several years apart, and IQ loss correlated with how many times they were diagnosed as cannabis-dependent at measurement so presumably length of time using). If you started as an adult, there was no clear correlation, although looks like at least a small trend towards decline was always observed. http://m.pnas.org/content/109/40/E2657/F2.expansion.html http://m.pnas.org/content/109/40/E2657/F2.expansion.html As far as reversal, looks like it stuck pretty hard if you started regular use during adolescence. If you started afterwards, then you bounced back as long as you weren't still using frequently. http://m.pnas.org/content/109/40/E2657/F3.expansion.html http://m.pnas.org/content/109/40/E2657/F3.expansion.html If your friends are adults it's probably either damage done already or nothing irreversible, at least to the extent this study is accurate. One thing that would be interesting would be a breakdown around different standard deviations. We know that drug use is higher in more intelligent people[1,2], and that probably does represent our audience here given subject matter. I'd be curious to know whether the effects are more or less marked once you're a couple of standard deviations out from the norm, given that the population measured seems to be near median-100 (i.e. either a broad cross-section or skewed towards average). [1] https://www.psychologytoday.com/blog/the-scientific-fundamentalist/201010/why-intelligent-people-use-more-drugs https://www.psychologytoday.com/blog/the-scientific-fundamen... [2] http://healthland.time.com/2011/11/15/why-kids-with-high-iq-are-more-likely-to-take-drugs/ http://healthland.time.com/2011/11/15/why-kids-with-high-iq-...
    - mirimir 9y ago
      > As far as reversal, looks like it stuck pretty hard if you started regular use during adolescence. If you started afterwards, then you bounced back as long as you weren't still using frequently. That makes sense. The human brain doesn't mature until the early 20s.
  - deleted 9y ago
    [deleted]
  - doktrin 9y ago
    Depending on when your stoner friends got started, they may or may not be self-reporting accurately. From the same link : > Our findings suggest that regular cannabis use before age 18 y predicts impairment, but others have found effects only for younger ages (10, 15). Given that the brain undergoes dynamic changes from the onset of puberty through early adulthood (37, 38), this developmental period should be the focus of future research on the age(s) at which harm occurs. Age of onset is a particularly important variable as it pertains to cannabis-induced cognitive impairment. I doubt cannabis is perfectly safe and harmless at any age, but it has consistently been shown to be both more harmful and less reversible to younger brains in development.
  - threepipeproblm 9y ago
    For some reason, most of the those who have promoted this piece have failed to notice that the same journal published a pretty scathing refutation of it, a few months later. http://www.pnas.org/content/110/11/4251.abstract http://www.pnas.org/content/110/11/4251.abstract It seems the original authors didn't even bother to look for confounding factors, such as socioeconomic status or use of other drugs.
    - threepipeproblm 9y ago
      It is also interesting to note that the paper cites only 3 "NIH grants", but the lead author works for the "Duke Transdisciplinary Prevention Research Center, Center for Child and Family Policy," which doesn't sound very objective. Hmm, let's dig further. The home page of the TPRC lists a single funder: the NDIA. https://childandfamilypolicy.duke.edu/project/transdisciplinary-prevention-research-center-tprc/ https://childandfamilypolicy.duke.edu/project/transdisciplin... That would be the National Institute on Drug Abuse, an institution which has a pre-established position on marijuana and other drugs, and stands to gain financially the more problems that are perceived with recreational drug use. The following government piece on drugabuse.org does not mention the serious criticisms, despite heavily quoting from the journal in which they were published 6 months prior. Since it streches credulity to think they didn't know about the problems raised, the logical conclusion is that the authors felt their piece would be stronger without mentioning them (versus offering any counter-rebuttal). https://www.drugabuse.gov/news-events/nida-notes/2013/08/early-onset-regular-cannabis-use-linked-to-iq-decline https://www.drugabuse.gov/news-events/nida-notes/2013/08/ear...
  - mattxxx 9y ago
    I think it's supposed to have a more damaging impact when you're younger, and your brain is rapidly developing.
    - geoelectric 9y ago
      I wonder if they corrected for differences in activity level. Pot has a habit of keeping you on the couch and away from more novel experiences and learning opportunities. Maybe being highly sedentary during brain development contributes. Wonder what the observation would be in sedentary-but-sober people.
  - steiger 9y ago
    A slight cognitive function decline is not at all that severe of a consequence, even if it is true. I'm pretty sure "brain damage" is true in some level for almost all recreational drugs. Amongst them, I'd say cannabis is a very forgiving drug of (ab)use.
- Hydraulix989 9y ago
  So it's at least on par with, if not safer and less harmful than other substances, including tobacco and alcohol, that are completely legal in all 50 states of our nation.
- mirimir 9y ago
  Downregulation is common in biological systems. With high-level THC exposures, one would expect downregulation of receptor density. And for high-level THC exposures during neurological development, one might also expect downregulation of connectivity. Which might eventually be irreversible. Conversely, with declining levels of endocannabinoids in older unexposed individuals, one might expect low-level THC exposures to improve function.
- jameslk 9y ago
  See also [0] for more on studies of the effects of cannabis on adolescents. Cannabis has also been claimed in studies of adults to have adverse effects on short term memory[1] and dopamine levels[2] with long-term use. 0. http://journal.frontiersin.org/article/10.3389/fpsyt.2013.00053/full http://journal.frontiersin.org/article/10.3389/fpsyt.2013.00... 1. http://jamanetwork.com/journals/jamainternalmedicine/article-abstract/2484906 http://jamanetwork.com/journals/jamainternalmedicine/article... 2. http://www3.imperial.ac.uk/newsandeventspggrp/imperialcollege/newssummary/news_1-7-2013-11-49-21 http://www3.imperial.ac.uk/newsandeventspggrp/imperialcolleg...
- erikpukinskis 9y ago
  Any dose of cannabis is going to be chronic.
to3m 9y ago
So counterintuitive that perhaps it has to be true! From around the same time, so presumably an alternative regurgitation of the same press release: http://www.birminghammail.co.uk/news/health/cannabis-could-help-reverse-memory-13005800 http://www.birminghammail.co.uk/news/health/cannabis-could-h... Choice quote: "But the benefits were only seen in older mice, said the researchers. When young animals were exposed to THC, their memory and learning performance got worse" - and I have to say that sounds more like my own experience of THC exposure as a young animal. But maybe I should take up the habit again in my dotage?
- mesozoic 9y ago
  Sure if you're a mouse
startupdiscuss 9y ago
The basic principle at play here is that anything that is enjoyable cannot be good for you. When you're young, and you do it recreationally, it is bad for you. As you grow older, and it becomes an annoying distraction from what you want to get done, it suddenly becomes beneficial.
- averagewall 9y ago
  I think that's because if something's enjoyable, you'll keep on doing it until either it stops being enjoyable or it causes some problem that makes you want to stop despite the enjoyment. By then it's either bad for you and enjoyable or not enjoyable and good for you. So I think your principle is a long term equilibrium position that things end up in, not really true in the short term.
- saiya-jin 9y ago
  incorrect. sex. love. adventures. travelling. making friends. and so on and on and on...
- fineline 9y ago
  So if one were to be in his or her late forties, say, when should one expect it to stop being enjoyable? A friend wanted to know ;)
  - rorykoehler 9y ago
    It depends. A friend knows for certain it can happen.
- realusername 9y ago
  This principle that "anything that is enjoyable cannot be good for you" is only there I suspect as a cultural leftover of the Catholic religion, I don't think it's a worldwide thing.
- deleted 9y ago
  [deleted]
exabrial 9y ago
Misleading title, it should probably say something like: Study shows THC in controlled micro doses appears to restore cognitive function in older mice
- erikpukinskis 9y ago
  "study shows", and "appears to" are filler. "In mice" is unnecessarily narrow as the original headline doesn't imply any species. "U.S. Drops Bombs" is a perfectly fine headline, the location can be specified in the article. What do you see as the distinction between "restore cognitive function in older individuals" vs "reverses aging process in the brain"?
  - exabrial 9y ago
    Did you actually click the link and read the title? Because that's what it says: "A chronic low dose of Δ9-tetrahydrocannabinol (THC) restores cognitive function in old mice"
bluetwo 9y ago
Anyone else think this is kind of a dubious news source?
- strict9 9y ago
  citation is in the article: https://www.nature.com/nm/journal/v23/n6/full/nm.4311.html https://www.nature.com/nm/journal/v23/n6/full/nm.4311.html
  - bluetwo 9y ago
    A much better source and title.
- valuearb 9y ago
  I'd find it more believable if the researchers didn't look so damn high in the picture.
mesozoic 9y ago
I hate these headlines for all medical research proven in mouse models. They should say "in mice" or "might" they're written to imply that it's already proven to work in humans.
- gadders 9y ago
  I heard a quote on a science podcast once to the effect of "If you can't cure cancer in mice, you're not really trying."
- erikpukinskis 9y ago
  What about the headline implies humans? And they did prove. There's no might, they measured it. It bugs me that people like you read things into headlines that aren't there and then complain that the headline didn't clarify your assumptions.
ForFreedom 9y ago
Cannabis is doing a lot of positive things to our body according to many reports How true is this all?
- agumonkey 9y ago
  you can go to pubmed.com and read, there's a lot of papers on THC and other cannabinoids https://www.ncbi.nlm.nih.gov/pubmed/?term=cannobinoids https://www.ncbi.nlm.nih.gov/pubmed/?term=cannobinoids Lots of research is related to Cancer, but there are some meta studies and non cancer related too.
- caub 9y ago
  probably with very small doses, and in any cases you're safer just eating better and doing exercises
- Hoasi 9y ago
  Not that surprising considering profits are changing hands.
ianai 9y ago
I've seen that merely adding new context and information to an aging brain helps it. Taking a psychedelic would definitely cause a brain to experience reality in new ways. For that reason alone, the added stimulation may be enough to enrich the connections.
- apk-d 9y ago
  Wouldn't that effect be statistically detectable, though? (personally a strong cannabis advocate, trying to avoid giving it mythical properties though)
agumonkey 9y ago
Tiny hint: there are hemp strains that are naturally low on THC (legal limit is low anyway) and also embed other cannabinoids like CBD (cannabidiol), which seems to be a potent anti inflammatory, and activates CB receptors (brain, GI tract). To summarize, it could be of use to grow non THC-heavy hemp and extract cannabinoids for your health.
- anentropic 9y ago
  it was the THC that had the positive effect in this study though
  - agumonkey 9y ago
    Yes, at low dose. Which legal hemp provider along with others.
    - leroy_masochist 9y ago
      You seem to be implying that "low-dose legal hemp" is a thing that exists....what do you mean?
      - fny 9y ago
        Health Canada defines hemp as products of Cannabis Sativa which contain less than 0.3 percent THC, whereas US law defines hemp as all parts of any Cannabis Sativa plant containing no psychoactive properties, except for defined exceptions
        agumonkey 9y ago
        I do not know us legislation, since medical majijuana is so trendy i expected hemp to be legal as well.
        agumonkey 9y ago
        I do not know us legislation, since medical majijuana is so trendy i expected hemp to be legal as well.
anentropic 9y ago
so... what age should I start smoking again?
- smashu 9y ago
  now
lngnmn 9y ago
Oh, so cannabis decreases entropy of the universe, how wonderful! I wish I could have a chance to smoke what they had. Ageing essentially is the same process as erosion of mountains. No amount of cannabis or LSD would help.
tempodox 9y ago
I guess it won't help with braindead [1] politicians who refuse to legalize it. [1] http://www.imdb.com/title/tt4877736/ http://www.imdb.com/title/tt4877736/

189 points by brahmwg 9y ago

I'm not sure its wise to say "Cannabis" as a shorthand for "Low doses of THC." The headline of the paper is: "A chronic low dose of Δ9-tetrahydrocannabinol (THC) restores cognitive function in old mice. https://www.nature.com/nm/journal/v23/n6/full/nm.4311.html" https://www.nature.com/nm/journal/v23/n6/full/nm.4311.html" Which is interesting, but you shouldn't take it to mean smoking is good for your brain. We already have some data to suggest that smoking cannabis, at least while young, is linked to cognitive decline. "Persistent cannabis users show neuropsychological decline from childhood to midlife" (2012) http://m.pnas.org/content/109/40/E2657.full http://m.pnas.org/content/109/40/E2657.full

justboxing 9y ago
From the 2nd Link: > Persistent cannabis use was associated with neuropsychological decline broadly across domains of functioning, even after controlling for years of education. Informants also reported noticing more cognitive problems for persistent cannabis users. Impairment was concentrated among adolescent-onset cannabis users, with more persistent use associated with greater decline. Further, cessation of cannabis use did not fully restore neuropsychological functioning among adolescent-onset cannabis users. Does the last sentence mean what I think it means. That even after stopping cannabis use, the neuropsychological damage / cognitive problems remained, and didn't rollback the decline from cannabis use? If yes, it's troubling. All my stoner friends claim no permanent damage from chronic use
- nerflad 9y ago
  Troubling, but not at all surprising
- simonsarris 9y ago
  > If yes, it's troubling. All my stoner friends claim no permanent damage from chronic use I mean, your stoner friends have got to be making a strange claim in the first place. There is no magic Twin Earth, where yoga is a contact sport, John McCain is president, and they never smoked, that they can compare themselves to. We all decline somewhat from other factors, the question is just how much is attributable to what. How would they even be able to parse out their cannabis-decline from their age-decline, or from their haven't-practiced-long-division-recently decline, etc? If they are only thinking "I felt dumber when smoking but now that I stopped, it seems gone", well, that's something, but it can't be a complete picture vs their never-smoked potential.
  - kgwxd 9y ago
    "There is no magic Twin Earth" That's just, like, your opinion man. If they smoke enough, they've probably been to Twin Earth.
    - TeMPOraL 9y ago
      They've probably been to many places. http://slatestarcodex.com/2015/04/21/universal-love-said-the-cactus-person/ http://slatestarcodex.com/2015/04/21/universal-love-said-the...
  - exabrial 9y ago
    Acroyoga: https://en.wikipedia.org/wiki/Acroyoga https://en.wikipedia.org/wiki/Acroyoga Does that count as full contact?
  - babyrainbow 9y ago
    I have this same thought when people say their didn't have any problems even after they got all the vaccine shots as a child, so it is completely safe... How did you compare you with your version who never had shots? Or how did any vaccination trials do it?
    - roywiggins 9y ago
      You compare populations. Did a group who got the vaccine have more problems than an otherwise identical group that didn't? This requires careful study design and statistical analysis, of course.
      - babyrainbow 9y ago
        > who got the vaccine have more problems than an otherwise identical group that didn't? But we were not talking about problems. The person I was replying said this > but it can't be a complete picture vs their never-smoked potential. So I am talking about the potential (meaning various capabilities IQ, Social behaviour, Emotional stability (withing the bound of normalcy) etc. I mean, things that are not usually recognized as problems..). How can you compare the potential of a version of you who never had vaccines with a version of you who had a given set of vaccines. This is particularly relevant with vaccines because you don't have a version of you before having vaccines, since these are usually administrated at a very young age..
- PhasmaFelis 9y ago
  I thought it was well-known that marijuana use among adolescents was a risk factor for schizophrenia. I'm 100% for legalization, but no drug is ever completely safe. I had to talk a friend down from a nasty paranoid dissociation episode after she ate the recommended dose of a mass-produced legal pot cookie in Seattle. It's a hell of a lot safer than alcohol, IMO, but that's not the same thing as "safe".
  - Hydraulix989 9y ago
    Yes, I've had friends who've had similar experiences after ingesting edibles. Yes, there is some element of responsibility when it comes to consumption (nothing in life is risk-free), but it's not to the point where it should be considered illegal, to say nothing of the ruined lives caused by having a bunch of non-violent offenders run through our judicial system because they "got high."
    - PhasmaFelis 9y ago
      Absolutely. The best solution in my mind is legalization and education. That's why it pisses me off when people spread the story that it's 100% harmless--you can't be a responsible user if you don't know the facts, positive and negative.
  - whiddershins 9y ago
    I think it is psychotic breaks you could be referring to. Schizophrenia is its own thing.
    - PhasmaFelis 9y ago
      The studies I've seen connect schizophrenia with marijuana use in young people. My friend's episode may be something else; it hasn't recurred despite ongoing occasional use, and she hasn't shown any other signs of schizophrenia that I'd recognize.
  - gehwartzen 9y ago
    Kind of a side thought but we have kind of a strange cultural definition of what constitutes a drug. There are plenty of common foods which have physiological and neurological affects.
- justifier 9y ago
  here is an illuminating issue with the trend of specifying interest as a science develops it usually branches into specific categories of study these categories and their proponents usually create language to simplify intercommunication of ideas but the issue becomes these placeholder words can sometimes be misunderstood: two parties each agreeing on a conclusion but holding different definitions for linking jargon; or sometimes are oversimplifications of their underlying ideas that are less interesting to the science being discussed what does neuropsychological mean? googs will tell you: the study of the relationship between behavior, emotion, and cognition on the one hand, and brain function on the other. wiki(o) will tell you: Neuropsychology studies the structure and function of the brain as they relate to specific psychological processes and behaviours so what is declining? the structure of the brain? how do you measure that? less neurons? less connections? do we know how many neurons or connections is ideal? or is behaviour and emotion declining? how do you determine desirability of emotion and behaviour? wiki also suggests methods of measuring this: https://en.wikipedia.org/wiki/Neuropsychology#Methods_and_tools https://en.wikipedia.org/wiki/Neuropsychology#Methods_and_to... ; which include card sorting(i) and brain scans the former suffering from what i would consider a fallacy of overfitting and the latter currently under scrutiny for overassuming(ii) it's also a young enough field that hn's spellchecker flags neuropsychology as a misspelled word.. perhaps the spellchecker's neuropsychology has been damaged do i care one way or the other on the short and long term damage from cannabis smoking? of course i am interested in the results but i hope in the future the language, from both sides, will become more descriptive and less inflammatory that said, much like with alcohol use, you are intentionally poisoning yourself in order to alter your perception of shared reality.. accelerated entropy should be expected but the more descriptive information we can form will better inform our decisions on whether the benefits outweigh the negatives (o) https://en.wikipedia.org/wiki/Neuropsychology https://en.wikipedia.org/wiki/Neuropsychology (i) https://en.wikipedia.org/wiki/Wisconsin_Card_Sorting_Test https://en.wikipedia.org/wiki/Wisconsin_Card_Sorting_Test (ii) https://www.theguardian.com/science/neurophilosophy/2015/apr/09/bold-assumptions-fmri https://www.theguardian.com/science/neurophilosophy/2015/apr...
  - Nav_Panel 9y ago
    > that said, much like with alcohol use, you are intentionally poisoning yourself in order to alter your perception of shared reality.. accelerated entropy should be expected This is an odd statement. Weed isn't exactly toxic like alcohol is. It's nearly impossible to overdose, any acute harm will be purely psychological (even though this thread is debating whether long-term harm can enter the physical realm). Also, we do all sorts of stuff all the time to alter our perception of reality, mostly not involving substances...
- deleted 9y ago
  [deleted]
- geoelectric 9y ago
  Well, if you read the results what it basically says is that if you started regular use from adolescence there was a clear IQ decline correlated in proportion with "waves" of diagnoses (iow, they measured a number of times several years apart, and IQ loss correlated with how many times they were diagnosed as cannabis-dependent at measurement so presumably length of time using). If you started as an adult, there was no clear correlation, although looks like at least a small trend towards decline was always observed. http://m.pnas.org/content/109/40/E2657/F2.expansion.html http://m.pnas.org/content/109/40/E2657/F2.expansion.html As far as reversal, looks like it stuck pretty hard if you started regular use during adolescence. If you started afterwards, then you bounced back as long as you weren't still using frequently. http://m.pnas.org/content/109/40/E2657/F3.expansion.html http://m.pnas.org/content/109/40/E2657/F3.expansion.html If your friends are adults it's probably either damage done already or nothing irreversible, at least to the extent this study is accurate. One thing that would be interesting would be a breakdown around different standard deviations. We know that drug use is higher in more intelligent people[1,2], and that probably does represent our audience here given subject matter. I'd be curious to know whether the effects are more or less marked once you're a couple of standard deviations out from the norm, given that the population measured seems to be near median-100 (i.e. either a broad cross-section or skewed towards average). [1] https://www.psychologytoday.com/blog/the-scientific-fundamentalist/201010/why-intelligent-people-use-more-drugs https://www.psychologytoday.com/blog/the-scientific-fundamen... [2] http://healthland.time.com/2011/11/15/why-kids-with-high-iq-are-more-likely-to-take-drugs/ http://healthland.time.com/2011/11/15/why-kids-with-high-iq-...
  - mirimir 9y ago
    > As far as reversal, looks like it stuck pretty hard if you started regular use during adolescence. If you started afterwards, then you bounced back as long as you weren't still using frequently. That makes sense. The human brain doesn't mature until the early 20s.
- deleted 9y ago
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- doktrin 9y ago
  Depending on when your stoner friends got started, they may or may not be self-reporting accurately. From the same link : > Our findings suggest that regular cannabis use before age 18 y predicts impairment, but others have found effects only for younger ages (10, 15). Given that the brain undergoes dynamic changes from the onset of puberty through early adulthood (37, 38), this developmental period should be the focus of future research on the age(s) at which harm occurs. Age of onset is a particularly important variable as it pertains to cannabis-induced cognitive impairment. I doubt cannabis is perfectly safe and harmless at any age, but it has consistently been shown to be both more harmful and less reversible to younger brains in development.
- threepipeproblm 9y ago
  For some reason, most of the those who have promoted this piece have failed to notice that the same journal published a pretty scathing refutation of it, a few months later. http://www.pnas.org/content/110/11/4251.abstract http://www.pnas.org/content/110/11/4251.abstract It seems the original authors didn't even bother to look for confounding factors, such as socioeconomic status or use of other drugs.
  - threepipeproblm 9y ago
    It is also interesting to note that the paper cites only 3 "NIH grants", but the lead author works for the "Duke Transdisciplinary Prevention Research Center, Center for Child and Family Policy," which doesn't sound very objective. Hmm, let's dig further. The home page of the TPRC lists a single funder: the NDIA. https://childandfamilypolicy.duke.edu/project/transdisciplinary-prevention-research-center-tprc/ https://childandfamilypolicy.duke.edu/project/transdisciplin... That would be the National Institute on Drug Abuse, an institution which has a pre-established position on marijuana and other drugs, and stands to gain financially the more problems that are perceived with recreational drug use. The following government piece on drugabuse.org does not mention the serious criticisms, despite heavily quoting from the journal in which they were published 6 months prior. Since it streches credulity to think they didn't know about the problems raised, the logical conclusion is that the authors felt their piece would be stronger without mentioning them (versus offering any counter-rebuttal). https://www.drugabuse.gov/news-events/nida-notes/2013/08/early-onset-regular-cannabis-use-linked-to-iq-decline https://www.drugabuse.gov/news-events/nida-notes/2013/08/ear...
- mattxxx 9y ago
  I think it's supposed to have a more damaging impact when you're younger, and your brain is rapidly developing.
  - geoelectric 9y ago
    I wonder if they corrected for differences in activity level. Pot has a habit of keeping you on the couch and away from more novel experiences and learning opportunities. Maybe being highly sedentary during brain development contributes. Wonder what the observation would be in sedentary-but-sober people.
- steiger 9y ago
  A slight cognitive function decline is not at all that severe of a consequence, even if it is true. I'm pretty sure "brain damage" is true in some level for almost all recreational drugs. Amongst them, I'd say cannabis is a very forgiving drug of (ab)use.
Hydraulix989 9y ago
So it's at least on par with, if not safer and less harmful than other substances, including tobacco and alcohol, that are completely legal in all 50 states of our nation.
mirimir 9y ago
Downregulation is common in biological systems. With high-level THC exposures, one would expect downregulation of receptor density. And for high-level THC exposures during neurological development, one might also expect downregulation of connectivity. Which might eventually be irreversible. Conversely, with declining levels of endocannabinoids in older unexposed individuals, one might expect low-level THC exposures to improve function.
jameslk 9y ago
See also [0] for more on studies of the effects of cannabis on adolescents. Cannabis has also been claimed in studies of adults to have adverse effects on short term memory[1] and dopamine levels[2] with long-term use. 0. http://journal.frontiersin.org/article/10.3389/fpsyt.2013.00053/full http://journal.frontiersin.org/article/10.3389/fpsyt.2013.00... 1. http://jamanetwork.com/journals/jamainternalmedicine/article-abstract/2484906 http://jamanetwork.com/journals/jamainternalmedicine/article... 2. http://www3.imperial.ac.uk/newsandeventspggrp/imperialcollege/newssummary/news_1-7-2013-11-49-21 http://www3.imperial.ac.uk/newsandeventspggrp/imperialcolleg...
erikpukinskis 9y ago
Any dose of cannabis is going to be chronic.

to3m 9y ago

So counterintuitive that perhaps it has to be true! From around the same time, so presumably an alternative regurgitation of the same press release: http://www.birminghammail.co.uk/news/health/cannabis-could-help-reverse-memory-13005800 http://www.birminghammail.co.uk/news/health/cannabis-could-h... Choice quote: "But the benefits were only seen in older mice, said the researchers. When young animals were exposed to THC, their memory and learning performance got worse" - and I have to say that sounds more like my own experience of THC exposure as a young animal. But maybe I should take up the habit again in my dotage?

mesozoic 9y ago
Sure if you're a mouse

startupdiscuss 9y ago

The basic principle at play here is that anything that is enjoyable cannot be good for you. When you're young, and you do it recreationally, it is bad for you. As you grow older, and it becomes an annoying distraction from what you want to get done, it suddenly becomes beneficial.

averagewall 9y ago
I think that's because if something's enjoyable, you'll keep on doing it until either it stops being enjoyable or it causes some problem that makes you want to stop despite the enjoyment. By then it's either bad for you and enjoyable or not enjoyable and good for you. So I think your principle is a long term equilibrium position that things end up in, not really true in the short term.
saiya-jin 9y ago
incorrect. sex. love. adventures. travelling. making friends. and so on and on and on...
fineline 9y ago
So if one were to be in his or her late forties, say, when should one expect it to stop being enjoyable? A friend wanted to know ;)
- rorykoehler 9y ago
  It depends. A friend knows for certain it can happen.
realusername 9y ago
This principle that "anything that is enjoyable cannot be good for you" is only there I suspect as a cultural leftover of the Catholic religion, I don't think it's a worldwide thing.
deleted 9y ago
[deleted]

exabrial 9y ago

Misleading title, it should probably say something like: Study shows THC in controlled micro doses appears to restore cognitive function in older mice

erikpukinskis 9y ago
"study shows", and "appears to" are filler. "In mice" is unnecessarily narrow as the original headline doesn't imply any species. "U.S. Drops Bombs" is a perfectly fine headline, the location can be specified in the article. What do you see as the distinction between "restore cognitive function in older individuals" vs "reverses aging process in the brain"?
- exabrial 9y ago
  Did you actually click the link and read the title? Because that's what it says: "A chronic low dose of Δ9-tetrahydrocannabinol (THC) restores cognitive function in old mice"

bluetwo 9y ago

Anyone else think this is kind of a dubious news source?

strict9 9y ago
citation is in the article: https://www.nature.com/nm/journal/v23/n6/full/nm.4311.html https://www.nature.com/nm/journal/v23/n6/full/nm.4311.html
- bluetwo 9y ago
  A much better source and title.
valuearb 9y ago
I'd find it more believable if the researchers didn't look so damn high in the picture.

mesozoic 9y ago

I hate these headlines for all medical research proven in mouse models. They should say "in mice" or "might" they're written to imply that it's already proven to work in humans.

gadders 9y ago
I heard a quote on a science podcast once to the effect of "If you can't cure cancer in mice, you're not really trying."
erikpukinskis 9y ago
What about the headline implies humans? And they did prove. There's no might, they measured it. It bugs me that people like you read things into headlines that aren't there and then complain that the headline didn't clarify your assumptions.

ForFreedom 9y ago

Cannabis is doing a lot of positive things to our body according to many reports How true is this all?

agumonkey 9y ago
you can go to pubmed.com and read, there's a lot of papers on THC and other cannabinoids https://www.ncbi.nlm.nih.gov/pubmed/?term=cannobinoids https://www.ncbi.nlm.nih.gov/pubmed/?term=cannobinoids Lots of research is related to Cancer, but there are some meta studies and non cancer related too.
caub 9y ago
probably with very small doses, and in any cases you're safer just eating better and doing exercises
Hoasi 9y ago
Not that surprising considering profits are changing hands.

ianai 9y ago

I've seen that merely adding new context and information to an aging brain helps it. Taking a psychedelic would definitely cause a brain to experience reality in new ways. For that reason alone, the added stimulation may be enough to enrich the connections.

apk-d 9y ago
Wouldn't that effect be statistically detectable, though? (personally a strong cannabis advocate, trying to avoid giving it mythical properties though)

agumonkey 9y ago

Tiny hint: there are hemp strains that are naturally low on THC (legal limit is low anyway) and also embed other cannabinoids like CBD (cannabidiol), which seems to be a potent anti inflammatory, and activates CB receptors (brain, GI tract). To summarize, it could be of use to grow non THC-heavy hemp and extract cannabinoids for your health.

anentropic 9y ago
it was the THC that had the positive effect in this study though
- agumonkey 9y ago
  Yes, at low dose. Which legal hemp provider along with others.
  - leroy_masochist 9y ago
    You seem to be implying that "low-dose legal hemp" is a thing that exists....what do you mean?
    - fny 9y ago
      Health Canada defines hemp as products of Cannabis Sativa which contain less than 0.3 percent THC, whereas US law defines hemp as all parts of any Cannabis Sativa plant containing no psychoactive properties, except for defined exceptions
      - agumonkey 9y ago
        I do not know us legislation, since medical majijuana is so trendy i expected hemp to be legal as well.
      - agumonkey 9y ago
        I do not know us legislation, since medical majijuana is so trendy i expected hemp to be legal as well.

anentropic 9y ago

so... what age should I start smoking again?

smashu 9y ago
now

lngnmn 9y ago

Oh, so cannabis decreases entropy of the universe, how wonderful! I wish I could have a chance to smoke what they had. Ageing essentially is the same process as erosion of mountains. No amount of cannabis or LSD would help.

tempodox 9y ago

I guess it won't help with braindead [1] politicians who refuse to legalize it. [1] http://www.imdb.com/title/tt4877736/ http://www.imdb.com/title/tt4877736/