

Brain changes are associated with casual marijuana use in young adults - denzil_correa
http://www.sfn.org/Press-Room/News-Release-Archives/2014/Brain-Changes-Are-Associated-with-Casual-Marijuana-Use-in-Young-Adults

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randomdrake
The research that is the subject of this article[1] made the rounds a few
months ago in the anti-cannabis movement. Here are some excerpts worth
repeating:

"Marijuana participants were not excluded if they had used other illegal drugs
in the past"

Also, in the 2nd to last paragraph (emphasis mine):

"This preliminary study has several caveats. First, the sample size does not
provide power to examine complex interactions such as sex differences.
_Because this is a cross-sectional study, causation cannot be determined,
although marijuana exposure parametrically correlated with structural
differences, which suggests the possibility of causation._ Longitudinal
studies are needed to determine whether marijuana exposure explicitly leads to
the differences observed in this study."

Checking out some of the players where the research money came from (National
Institute on Drug Abuse, the Office of National Drug Control Policy,
Counterdrug Technology Assessment Center), it is no wonder the various news
articles and the paper itself tried so hard to illustrate some causation. They
ended up with a handful of people and some correlative results.

[1] -
[http://jn.sfn.org/press/April-16-2014-Issue/zns01614005529.p...](http://jn.sfn.org/press/April-16-2014-Issue/zns01614005529.pdf)

~~~
araes
Its fairly apparent in the way they write and structure the article too. It
starts from an assumption, "marijuana = bad". Although they honestly may not
be aware of it. They make sentences like:

"Marijuana use is often associated with motivation, attention, learning, and
memory impairments. Previous studies exposing animals to THC show that
repeated exposure to the drug causes structural changes in brain regions
involved with these functions"

Which implies, but doesn't actually state, that marijuana use makes you "less
motivated, less attentive, unable to learn, and memory impaired" in the long
term (ie, not just when smoking) and then finish with:

"This study raises a strong challenge to the idea that casual marijuana use
isn’t associated with bad consequences"

Without actually showing "bad" in any of the results, just "change".

Admittedly, anecdotal evidence of the "stoner" stereotype from most folks on
the street might say that (while smoking) those are probably true. I'm all for
folks knowing the risks of things they choose to ingest. But I'd rather we can
choose, and most of the people smoking might also say they don't mind.

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DanBC
One of the problems with the illegality of cannabis is that research is
terrible because of the laws.

I strongly favour legalisation of all drugs. This would allow much better
research.

Having said that the knee-jerk denialism that cannabis could possibly cause
any harm at all is weird to see on HN.

~~~
kingnothing
Where do you draw the line in legalizing drugs, though? It's a question I
often ask myself and others when we start discussing legalization and
decriminalization. For example, should everyone be able to buy antibiotics and
antivirals OTC without a prescription?

~~~
hnnewguy
> _should everyone be able to buy antibiotics and antivirals OTC without a
> prescription?_

Of course not. But what does this have to do with legalization? Antibiotics
and antivirals are legal and controlled, just like marijuana should be.

~~~
seanflyon
In the current legalization debate "legal" generally means legal without a
prescription. Those who want it to be legal but only with a prescription
generally use the term "medical marijuana" instead of "legalization".

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jahewson
Playing Super Mario is also associated with brain changes [1]. Perhaps the
answer is simply that as humans, our brains change quite a lot in response to
our habits, and that such changes are unremarkable.

1\.
[http://www.nature.com/mp/journal/v19/n2/full/mp2013120a.html](http://www.nature.com/mp/journal/v19/n2/full/mp2013120a.html)

~~~
kennywinker
I'm with you all the way up to "unremarkable". We're still trying to
understand the brain, so any observation of change is probably interesting and
helpful to our understanding.

I for one would love to see a long term study on the effects of learning to
program on your brain. After long coding sessions I often find it challenging
to communicate effectively with friends or to follow complex social
interactions. It's clear to me that focusing on abstract ideas for extended
periods has a short term effect, and I would have to guess it has a long term
one as well.

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doragcoder
I'm naive here, but won't some brain changes have to happen when becoming
addicted to nicotine when smoking cigarettes?

Would it be safe to say that, any drug that alters your state of mind will
cause a brain change? (Legal or illegal)

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far33d
It's amazing to me that medical journals print results based on 20 control and
20 test subjects.

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tormeh
I remember sitting at a table with some neuroscientists in Berlin, and it
turned out that they all smoked from time to time. They were really casual
about it. Sure, marijuana is bad but alcohol is worse and we all do that.

This study presents an extraordinary claim but, if the comments mentioning of
20 subjects are correct, does not present extraordinary evidence.

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josephschmoe
|In the current study, Jodi Gilman, PhD, Anne Blood, PhD, and Hans Breiter,
MD, of Northwestern University and Massachusetts General Hospital/Harvard
Medical School used magnetic resonance imaging (MRI) to compare the brains of
18- to 25-year olds who reported smoking marijuana at least once per week with
those with little to no history of marijuana use.

Most people who consume marijuana regularly would not admit that information.
This is not and cannot be a representative sample. Also correlation causation
problems and tiny (20 people) sample size.

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VonGuard
Yeah, 20 people doesn't make a study, it makes a basis for forming a
hypothesis for potentially going after a grant to actually do a study.

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JamesBarney
The biggest problem with this study is a huge selection effect. The users of
marijuana are very different then non users, and heavy users are very
different from light light users. This by itself would show large correlations
across a large swath of measurements.

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jacquesm
Anybody over 50 here that uses marijuana regularly and is still sharp?

That's an honest question, my own connections do not include programmers over
50 that smoke marijuana regularly so I'm curious how many people would bill
themselves as such.

~~~
michaelvkpdx
I've known several. "Sharp" isn't necessarily the right adjective for them,
but they have all been excellent problem solvers. Sharpness is for young
programmers, with or without weed.

I must say that I do not know any programmers who have lasted into their 50's
without being regular stoners. Something about cannabis seems to protect them
from the dementia that is so prevalent among people in this field 20 or more
years.

Relative to this article, though- even though I'm a big advocate of the herb
I'm familiar with the research done in Israel, Spain, and elsewhere, and one
common thread is that cannabis alters the growing brain in ways that may not
be desirable. I wish we could talk to our kids intelligently about it. Whether
it's legal or not, it is not a good idea for a teenager to smoke a lot of
weed. One puff isn't going to kill you, but once a week might impact your
brain, and give you less psychic space to explore when you get high later in
life.

Patience, children!

I've always used a company's drug-testing policy as a litmus test. If they
test for cannabis, I know that they are limiting their pool severely, and that
they will not get a number of the best programmers.

~~~
Catalyst4NaN
Is dementia common among programmers? I'd never heard that before

~~~
michaelvkpdx
Well, maybe it's just seasonal affective disorder, or Portlanders being weird,
but every programmer I've known who's been in the field longer than maybe 15
years is a little bonkers.

I wish there was a good study on mental health in aging programmers, to
validate what has always been obvious from experience. We have a shelf life.
This work is challenging and affects your brain chemistry if you spend your
career constantly immersed in difficult programming tasks.

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dyeje
Are brain changes an inherently bad thing?

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lazyant
btw, didn't the US pass a law to defund research on marijuana?

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revscat
tl;dr: "The scientists found that the more the marijuana users reported
consuming, the greater the abnormalities in the nucleus accumbens and
amygdala. The shape and density of both of these regions also differed between
marijuana users and non-users."

Nucleus accumbens: responsible for pleasure & reinforcement, maternal
behavior. Direct stimulation has been shown to successfully decrease the
effects of depression.

Amygdala: Responsible for emotional learning, memories of emotional
experiences, memory consolidation, and emotional regulation.

All sources Wikipedia. I am not a neuroscientist, just trying to get a better
understanding.

~~~
kennywinker
It's important to note that the study itself seems to make no mention of
negative effects. Change yes, but not all change is negative. The article
casts this as proof that marijuana is bad for you, but the study itself only
notes evidence of an effect on brain structure... Not what the change means in
real world terms.

~~~
whiskeySix
Exactly. This was my first response to the study. Came to the comments to see
if anyone could shed any light on the real world implications of this study.

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lelifer
"was larger and altered in its shape" that makes sense because when i'm high i
can feel much more emotion... with small animals.

