Casual marijuana use linked to brain abnormalities in students

Young adults who used marijuana only recreationally showed significant abnormalities in two key brain regions that are important in emotion and motivation, scientists report. The study was a collaboration between Northwestern Medicine and Massachusetts General Hospital/Harvard Medical School.

This is the first study to show casual use of is related to major changes. It showed the degree of brain abnormalities in these regions is directly related to the number of joints a person smoked per week. The more joints a person smoked, the more abnormal the shape, volume and density of the brain regions.

"This study raises a strong challenge to the idea that casual marijuana use isn't associated with bad consequences," said corresponding and co-senior study author Hans Breiter, M.D. He is a professor of psychiatry and behavioral sciences at Northwestern University Feinberg School of Medicine and a psychiatrist at Northwestern Memorial Hospital.

"Some of these people only used marijuana to get high once or twice a week," Breiter said. "People think a little recreational use shouldn't cause a problem, if someone is doing OK with work or school. Our data directly says this is not the case."

The study will be published April 16 in the Journal of Neuroscience.

Scientists examined the and the amygdala—key regions for emotion and motivation, and associated with addiction—in the brains of casual marijuana users and non-users. Researchers analyzed three measures: volume, shape and density of grey matter (i.e., where most cells are located in brain tissue) to obtain a comprehensive view of how each region was affected.

Both these regions in recreational pot users were abnormally altered for at least two of these structural measures. The degree of those alterations was directly related to how much marijuana the subjects used.

Of particular note, the nucleus acccumbens was abnormally large, and its alteration in size, shape and density was directly related to how many joints an individual smoked.

"One unique strength of this study is that we looked at the nucleus accumbens in three different ways to get a detailed and consistent picture of the problem," said lead author Jodi Gilman, a researcher in the Massachusetts General Center for Addiction Medicine and an instructor in psychology at Harvard Medical School. "It allows a more nuanced picture of the results."

Examining the three different measures also was important because no single measure is the gold standard. Some abnormalities may be more detectable using one type of neuroimaging analysis method than another. Breiter said the three measures provide a multidimensional view when integrated together for evaluating the effects of marijuana on the brain.

"These are core, fundamental structures of the brain," said co-senior study author Anne Blood, director of the Mood and Motor Control Laboratory at Massachusetts General and assistant professor of psychiatry at Harvard Medical School. "They form the basis for how you assess positive and negative features about things in the environment and make decisions about them."

Through different methods of neuroimaging, scientists examined the brains of , ages 18 to 25, from Boston-area colleges; 20 who smoked marijuana and 20 who didn't. Each group had nine males and 11 females. The users underwent a psychiatric interview to confirm they were not dependent on marijuana. They did not meet criteria for abuse of any other illegal drugs during their lifetime.

The changes in brain structures indicate the marijuana users' brains are adapting to low-level exposure to marijuana, the scientists said.

The study results fit with animal studies that show when rats are given tetrahydrocannabinol (THC) their brains rewire and form many new connections. THC is the mind-altering ingredient found in marijuana.

"It may be that we're seeing a type of drug learning in the brain," Gilman said. "We think when people are in the process of becoming addicted, their brains form these new connections."

In animals, these new connections indicate the brain is adapting to the unnatural level of reward and stimulation from marijuana. These connections make other natural rewards less satisfying.

"Drugs of abuse can cause more dopamine release than natural rewards like food, sex and social interaction," Gilman said. "In those you also get a burst of dopamine but not as much as in many drugs of abuse. That is why drugs take on so much salience, and everything else loses its importance."

The brain changes suggest that structural changes to the brain are an important early result of casual drug use, Breiter said. "Further work, including longitudinal studies, is needed to determine if these findings can be linked to animal studies showing marijuana can be a gateway drug for stronger substances," he noted.

Because the study was retrospective, researchers did not know the THC content of the marijuana, which can range from 5 to 9 percent or even higher in the currently available drug. The THC content is much higher today than the marijuana during the 1960s and 1970s, which was often about 1 to 3 percent, Gilman said.

Marijuana is the most commonly used illicit drug in the U.S. with an estimated 15.2 million users, the study reports, based on the National Survey on Drug Use and Health in 2008. The drug's use is increasing among adolescents and young adults, partially due to society's changing beliefs about cannabis use and its legal status.

A recent Northwestern study showed chronic use of marijuana was linked to . "With the findings of these two papers," Breiter said, "I've developed a severe worry about whether we should be allowing anybody under age 30 to use pot unless they have a terminal illness and need it for pain."

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zoljah
4.4 / 5 (7) Apr 15, 2014
"The THC content is much higher today than the marijuana during the 1960s and 1970s, which was often about 1 to 3 percent, Gilman said."

That moment.. when you know.. resist the ignorance.
Protoplasmix
4.2 / 5 (15) Apr 15, 2014
Ten out of ten on the propaganda scale. Compared to cigarettes, alcohol, coke, meth and heroin, and various prescription meds, marijuana isn't even remotely close to being physically addicting. MJ isn't the gateway drug—the simple sugar buzz inarguably is. No such thing as an overdose on MJ—not true for alcohol, coke, meth and heroin, as well as various prescription meds. The word "abnormal" was used seven times in the article, rather than "altered", "enlarged", or "enhanced". Looks like evidence of enhanced neuroplasticity in rats: "when rats are given tetrahydrocannabinol (THC) their brains rewire and form many new connections". People do not get in fights after smoking a joint, while fights are commonplace when alcohol is consumed. In fact the only violence associated with MJ is over the huge amount of money that sales of it generate.
gculpex
4.4 / 5 (7) Apr 15, 2014
Compared to cigarettes, alcohol, coke, meth and heroin, and various prescription meds, marijuana isn't even remotely close to being physically addicting.

SOoooo, like, you know, i would believe you but, but I really don't care. LOLl.

NO, reallly, I smoke it, this stuff before and i, and I'm okay...... with it.

Wolf358
3.9 / 5 (8) Apr 15, 2014
If long-term marijuana use alters these brain structures, what effect does that have on personality? Any? Does it make people more prone to violence and crime? It seems not... so what's the problem again? Oh! We need to waste more money researching non-problems... Yeah...
Zera
4.6 / 5 (10) Apr 15, 2014
Translation: I am reading from the mission statement, given to our research group, by the people paying all our salaries. I went looking for any anectdotal linkage, within the smallest test group I could find and then jumped to all sorts of assumptions as a result. I then went on to quote some really terribly old and disproven propoganda, but you know once something has been said, the listener has it in their head, whether it is true or not.

Why do you think they use the words abnormal, and not damaged... why do you think they don't describe the action that these expanded accumbens perform?

I mean attitudinal bias is present, where is the peer review? Is this some kind of joke?

Whether we should allow? How about you allow each individual the liberty to choose?
satanfornoreason
4.6 / 5 (9) Apr 16, 2014
What a joke. These researchers have lost all credibility. Variation in brain structures could be due to ANYTHING genetic or environmental. These researchers claim that it is marijuana.

They are worried about people under 30 smoking marijuana. Give me a break.

It is no one's business whether I smoke marijuana or other drugs, and I have a right as a citizen exercising my own free will whether or not I take the risk of skydiving or take the risk of smoking marijuana. It's no one's business and people should not be punished for having recreational drugs. End of story.

Not just marijuana, but cocaine & meth & LSD & ecstacy too. Legalizing these doesn't mean they can't be regulated. It also doesn't mean everyone can take them. Professionals such as surgeons & plane pilots should continue to be tested. But there is no good reason to punish people for having these substances.

If they cause undesirable behavior changes, then punish that behavior if it is illegal. Don't punish use.
kienhoa68
5 / 5 (5) Apr 16, 2014
Only twenty in each group? How long was the study? How 'normal' was the control group? It makes sense that young people should be very careful. Honestly it best serves the old. It should be available in all old age homes.
big_hairy_jimbo
4.2 / 5 (5) Apr 16, 2014
I loved this sentence;
"One unique strength of this study is that we looked at the nucleus accumbens in three different ways to get a detailed and consistent picture of the problem,"

Oh, that sounds very scientific and impartial. Or was it loaded?? Hmmm, they said the strength of the study was to get a detailed picture of the problem. Hmmm PROBLEM.
Sounds like they performed this very small study to find a PROBLEM, yet all they found were altered brain structures, which of course they called ABNORMALITIES!!!

The wording of this article is shonky as hell and full of biased language.
Now if they show these "abnormalities" to cause disease, or mid to long term physical detriment then I will listen, but what exactly are they saying they found, other than the brain responded to a neurological agent? Is this somehow different to pharmaceuticals that act on the brain or is it simply WHERE you get your drugs FROM that matters???
big_hairy_jimbo
5 / 5 (3) Apr 16, 2014
Damned system just ate my post!!!!

Anyway I loved this sentence;

"One unique strength of this study is that we looked at the nucleus accumbens in three different ways to get a detailed and consistent picture of the problem,"

That doesn't sound biased does it??? So they looked, but not to gather information for research, but to get a CONSISTENT PICTURE OF THE PROBLEM. Ohhh, you expected to find a problem and therefore word everything as such!!! Nice research!!!
ThomasQuinn
4.3 / 5 (6) Apr 16, 2014
All I see here is scientists studying a TINY group, seeing variations in brain structure, and jumping to the conclusion that THC is responsible. It might just be me, but I thought the scientific approach would be to eliminate the possibility that other factors are involved first, then testing the hypothesis on larger groups and refining the outcome before jumping to conclusions. This does not sound like solid scientific research to me.
pandora4real
4.3 / 5 (6) Apr 16, 2014
What a load of pre-conceived ideas! There are physical brain changes. And??? Where's the evidence that those changes don't lead to *different* functioning? Where's the evidence that the *person* finds those changes problematic? Yeah, you know if I work out my muscle mass increases dramatically. And it's directly correlated to how much I exercise. Oh, my. Exercising causes abnormally large muscles...
version782
5 / 5 (5) Apr 16, 2014
It changed brain structure so that automatically means it is bad? Learning to play an instrument changes brain structure, so is that bad too? Assuming an ambiguous result is a negative effect shows an obvious bias. Marijuana is an incredible drug that has many proven medical uses as well as being a safe recreational drug. The people that fund this garbage are the same scumbags that approve anti-depressants and stimulants for use on children.
Davralon
5 / 5 (4) Apr 16, 2014
Again, more propaganda funded by the narrow minded. Very vague with absolutely no substance, please, if your going to do these "research projects" at least do them on something that's worth doing like cancer research. Go home, nobody wants to hear your lies! Damn pharmaceutical companies!
holoman
4 / 5 (4) Apr 16, 2014
Its all about money, who has it, who wants it, and who wants to make it.

Ask the Kennedy's, Rockefellors.
JIMBO
5 / 5 (4) Apr 16, 2014
KUDOS to Protoplasmix & gculpex for seeing the light thru the maze of propaganda BS behind this research, which today is appearing in almost ALL news sources. We've seen this technique employed for decades: Scream bloody murder about "The Children" to induce paranoia in the masses of asses who want to sustain the drug war, despite the shining sanity of WA & CO. This was shamelessly employed in the last weeks prior to the vote on Prop19 in Calif. in 2010, & is behind OR dragging its feet on legalization.
When I used to live in Boulder, CO decades ago, such a technique was front pg. news, citing a `higher-than-national average use of psychedelics' among Boulder HS students. Possibly true. Missing however was the Fact that Boulder HS students have higher than average SAT scores, & as such, are regularly admitted to prestigious universities.
gculpex
not rated yet Apr 16, 2014
There must be sheeple, always....
no fate
4 / 5 (5) Apr 16, 2014
Excellent comments guys. An armada of health benefits vs. an agenda driven study and article that had to be written somewhat truthfully, hence the vagueries regarding the specific effects (no negative were listed) and what the results of these effects are.

MandoZink
5 / 5 (8) Apr 16, 2014
It has been know for years that early exposure to music lesson causes abnormalities in your corpus callosum.

In rats it is known to be a gateway to polka.
ziphead
5 / 5 (5) Apr 16, 2014
Lots of hi-fiving happening on this thread.
Rating-wise, I mean.

kochevnik
3 / 5 (2) Apr 17, 2014
Since when is "normal" the golden standard? Are average marks in school the most desirable? Doesn't education cause abnormal changes in the brains of surgeons and quantum physicists? They are no longer capable of vivid conversations with morons.
Steven_Gaylord
1.8 / 5 (5) Apr 18, 2014
This looks like Zionist media misinformation. Pure propaganda...
tpq
4 / 5 (4) Apr 18, 2014
I agree there should be freedom of choice to use pot or not, however those who want to be informed of the possible effects and consider whether they want to be affected this way, this is useful piece of research. Whether you believe it or not is another matter, to me the results seem statistically sound, especially with a link to the amount vs. the scale of changes.

The challenging bit comes from combining results from small human studies to animal studies in the same article. The actual effects need to be verified in humans, but wouldn't that be logical? If there are changes in the brain, that would correspond to behavioural changes? In this case loosing interest on other, less rewarding activities? I certainly wouldn't want to bias my life so that I only get rewards from a single source, or at least reduce the reward from other sources.

I seem to be the only commentard on this side of the field so let the slaughter begin...
ViperSRT3g
5 / 5 (1) Apr 18, 2014
My favorite line from this article was this:

"Because the study was retrospective, researchers did not know the THC content of the marijuana"

The study wasn't conducted live, they had to go back and review the results of an already-performed experiment and simply analyze the results. They didn't even know how much THC was even used in the experiment. All they had to go by was the measurements of each brain section.
Ratfish
2.6 / 5 (5) Apr 18, 2014
There's nothing remotely surprising about this. Flooding your system with any psychoactive substance is going to cause compensatory measures. Manual overrides, whether they're plant-derived or synthetic pharmaceuticals are always going to have unforeseen consequences.

Reading these comments and those posted elsewhere on the subject, you'd think that THC is an essential nutrient, without which we cannot survive.

You're all in denial and can't function in the real world without these crutches. Pathetic.
Wolf358
5 / 5 (1) Apr 19, 2014
Essential nutrient? Probably not. However,... http://en.wikiped...d_system and the folk who produced this "study" appear to depend on the crutch of Bad Science.
MichaelChase
5 / 5 (2) Apr 19, 2014
@Ratfish

The very last line of your post is the type of reaching that goes along perfectly with this article. Your previous words were totally sensible and I agreed wholeheartedly - the brain is going to react to substances that cause chemical release, etc. and thus these effects should always be considered, no matter how safe a substance is, but any credibility you had in my mind was instantly destroyed by that last line.

"Pathetic" is your attempt to make a reasonable argument and wrap it up with that statement.

I'm assuming you don't ever consume anything sweet? Or perhaps drink alcohol? Or, for that matter, drink anything other than water? Since those things are all very much "crutches" in the way you describe.
sdrfz
5 / 5 (3) Apr 19, 2014

This study was partly funded by the Office of Drug Control Policy in the US Federal government. So of course the government is going to fund research which shows MJ to be harmful, and ignore all data which proves otherwise.
Diogenes Tha Dogg
5 / 5 (1) Apr 19, 2014
Hey, I'm like, pro-weed and all. But y'alls need to chill out (ironic that a story about weed causes so much agitation, right?). Everything causes the brain's layout/shape/volume/etc to change - new memories, aging, traumatic events, non-traumatic events w/ large emotional import, etc.

If you have a round, red, fibrous bump on your arm, it's nice to know that "that round, red, fibrous bump" is actually called a "that benign fibrous histiocytoma". For credibility's sake, it would be useful for EVERY effect of weed to be meticulously mapped out, no matter how uninteresting. "It's totally good for you, man" it's wholly unconvincing and mentally sloppy. I'm sure weed is harmless but I'm also sure others disagree. The proof is for them, not "us".

Also: it's not exactly headline news that The Brain™ Adapts to A Thing, since the brain is the organism which that wherefore etc & Adaptation.
antigoracle
1 / 5 (1) Apr 20, 2014
Hmmmm.... what were these guys smoking?
Returners
1.7 / 5 (6) Apr 20, 2014
It's shocking how ignorant people on this thread really are.

The control group would be a sample of people who self-report as not having used Marijuana.

The test group are people who self report as regularly using Marijuana.

Since the only thing you are varying is Marijuana, you can be highly certain that the cause of the changes is Marijuana.

That's the point of the control group.

It is highly typical of addicts to defend their negative behaviors, even in the face of mounting evidence.
Protoplasmix
4.2 / 5 (5) Apr 20, 2014
It is highly typical of addicts to defend their negative behaviors, even in the face of mounting evidence

But marijuana is not addictive. Why are you in denial about that?

The only reason marijuana is pseudo-prohibited is because if it wasn't, people could grow it on their windowsill with no worries, and the government wouldn't even be able to tax it. It would be impossible for anyone to make money off it. How does it feel to be a misinformed idiot, Returners?
TheGhostofOtto1923
1 / 5 (2) Apr 20, 2014
People do not get in fights after smoking a joint
Well that's not true. I have seen this myself. Here is also documentation.
http://youtu.be/zXX9kJODA5U
Protoplasmix
5 / 5 (1) Apr 20, 2014
@Returners: and as far as 'in the face of mounting evidence,' you are facing a list as long as your arm—and growing—of benefits regarding a variety of different physiologies, circumstances and conditions.
Protoplasmix
5 / 5 (1) Apr 20, 2014
People do not get in fights after smoking a joint
Well that's not true. I have seen this myself. Here is also documentation.
http://youtu.be/zXX9kJODA5U

Pfffffffffftt, funny.
Returners
1.8 / 5 (5) Apr 20, 2014
@Returners: and as far as 'in the face of mounting evidence,' you are facing a list as long as your arm—and growing—of benefits regarding a variety of different physiologies, circumstances and conditions.


Medical use, with a prescription and properly processed compounds, is not the same thing as recreational use.
Protoplasmix
3 / 5 (2) Apr 20, 2014
Medical use, with a prescription and properly processed compounds, is not the same thing as recreational use.

Correct. Good for you, Returners, good for you. If that's an apology for expressing shock over "how ignorant people on this thread really are," then I accept. Others you've offended may not be as gracious.
FastEddy
not rated yet Apr 21, 2014
"Young adults who used marijuana only recreationally showed significant abnormalities in two key brain regions that are important in emotion and motivation, scientists report. ..."

Yes, it does read like propaganda ... But, dude! , just because it reads like fear mongering, does not mean its not true. (Or are you too stoned to appreciate a double negative ... Duh?)
FastEddy
1 / 5 (1) Apr 21, 2014
This study was partly funded by the Office of Drug Control Policy in the US Federal government. So of course the government is going to fund research which shows MJ to be harmful, and ignore all data which proves otherwise.


So similar to arguments made by Al Gore's Fear of Global Warming Church, and the collection plates are being passed around in DC.

But Dude! "... abnormalities in two key brain regions that are important in emotion and motivation ..."

Sounds just like it is ...

Wolf358
not rated yet Apr 21, 2014
EnricM
not rated yet Apr 22, 2014
"The THC content is much higher today than the marijuana during the 1960s and 1970s, which was often about 1 to 3 percent, Gilman said."

That moment.. when you know.. resist the ignorance.


Hmm, the percentage considered legal is 4%, under this THC concentration marihuana is not considered such but common hemp. Should I consider this study as reliable?
Note that I am not a drug user but an athlete (ultra-runner), I am not in favour of drugs but neither am I of misleading information.
EnricM
not rated yet Apr 22, 2014
"Young adults who used marijuana only recreationally showed significant abnormalities in two key brain regions that are important in emotion and motivation, scientists report. ..."

Yes, it does read like propaganda ... But, dude! , just because it reads like fear mongering, does not mean its not true. (Or are you too stoned to appreciate a double negative ... Duh?)


What it doesn't say is what these alterations mean and if these are negative, positive or nothing at all. Another thing that is not mentioned: Did these structures become altered _after_ using marihuana or was the study done comparing a group of recreational smokers with non-smokers?

More: Is this only related to THC or also to other drugs? Because there seems to be an implication that this is a common mechanism to explain addiction or at least "satisfaction" of drug use. And in this case: What happens with booze? I assume that even the 'non-pot-smoking' group was having a few beers from time to time.