Brain changes are associated with casual marijuana use in young adults | Hacker News Reader

Brain changes are associated with casual marijuana use in young adults

sfn.org

27 pointsdenzil_correa33 comments

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...

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.

People in the anti-cannabis movement think that the slightest hint to a potential toxicity of cannabis is good enough to justify its interdiction. The concept of freedom is totally foreign to them.

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.

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?

Obviously you need some controls - noone under 18; registration for opiates; prescription only use for some meds.

You could be dynamically responsive to black market demand. If there is high black market demand, make it available more easily through legal channels. In the case of antibiotics and antivirals I do not currently see high black market demand.

In my opinion, possession should be legalized in every case; it's not the government's business what I choose to put into my own body. In the case of dangerous drugs and medications it should be distribution / intent to distribute that's regulated.

The problem with misuse of antibiotics is not what it does to you but the risk it carries for the rest of society.

Speaking of anti-biotics: we really need clear easy to understand information for places that allow antibiotics over the counter, sometimes in single doses not full courses. This would tell people aboutthe harm they are doing to themselves and to the rest of society.

>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.

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".

I don't see any knee jerk denialism in the comments, just a fair helping of skepticism. This study is hardly a slam dunk, so skepticism seems appropriate. Especially because the article insinuates harm, when the study only indicates "change".

"Especially because the article insinuates harm, when the study only indicates 'change'."

I had the same thought. There are all sorts of behaviors that could conceivably cause structural changes in various regions of the brain - meditation, writing code for hours every day, moving to the jungle and becoming a hunter-gatherer, using legal drugs like SSRIs, etc. Since very few studies have been made of the neurological effects of various behaviors, we have no idea how common such changes are or whether they're harmful.

Also, what's the definition of "harmful"? We'd probably all agree that something that causes dementia is harmful, but if someone becomes a little worse at concentrating on work but feels better, is that evidence of harm?

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

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.

Super Mario is no joke. Those mushrooms will alter the size of your cranial cavity.

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)

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

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.

|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.

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.

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.

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.

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.

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

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.

I play music with a lot of old hippies (55-75, which to me isn't truly decrepitly old, but I'm 36 so these aren't folks I consider to be "my" age group). I gave up smoking about the time I turned 30.

The guys who smoke don't seem any less sharp than the other folks I know in those age groups, and they seem on par with the other folks I know of all age groups when they are smoking. So yah, I know plenty of wise old guys who regularly smoke.

Are brain changes an inherently bad thing?

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

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.

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.

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.

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

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