Northwestern study: Marijuana users have abnormal brain structure and poor memory

godkiller

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MARIJUANA USERS HAVE ABNORMAL BRAIN STRUCTURE AND POOR MEMORY
Drug abuse appears to foster brain changes that resemble schizophrenia
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December 16, 2013 | by Marla Paul
  • The younger drug abuse starts, the more abnormal the brain
CHICAGO --- Teens who were heavy marijuana users -- smoking it daily for about three years -- had abnormal changes in their brain structures related to working memory and performed poorly on memory tasks, reports a new Northwestern Medicine® study.

A poor working memory predicts poor academic performance and everyday functioning.

The brain abnormalities and memory problems were observed during the individuals’ early twenties, two years after they stopped smoking marijuana, which could indicate the long-term effects of chronic use. Memory-related structures in their brains appeared to shrink and collapse inward, possibly reflecting a decrease in neurons.

The study also shows the marijuana-related brain abnormalities are correlated with a poor working memory performance and look similar to schizophrenia-related brain abnormalities. Over the past decade, Northwestern scientists, along with scientists at other institutions, have shown that changes in brain structure may lead to changes in the way the brain functions.


This is the first study to target key brain regions in the deep subcortical gray matter of chronic marijuana users with structural MRI and to correlate abnormalities in these regions with an impaired working memory. Working memory is the ability to remember and process information in the moment and -- if needed -- transfer it to long-term memory. Previous studies have evaluated the effects of marijuana on the cortex, and few have directly compared chronic marijuana use in otherwise healthy individuals and individuals with schizophrenia.

The younger the individuals were when they started chronically using marijuana, the more abnormally their brain regions were shaped, the study reports. The findings suggest that these regions related to memory may be more susceptible to the effects of the drug if abuse starts at an earlier age.

“The study links the chronic use of marijuana to these concerning brain abnormalities that appear to last for at least a few years after people stop using it,” said lead study author Matthew Smith, an assistant research professor in psychiatry and behavioral sciences at Northwestern University Feinberg School of Medicine. “With the movement to decriminalize marijuana, we need more research to understand its effect on the brain.”

The paper was published Dec. 16 in the journal Schizophrenia Bulletin.

In the U.S., marijuana is the most commonly used illicit drug and young adults have the highest -- and growing -- prevalence of use. Decriminalization of the drug may lead to greater use.

Because the study results examined one point in time, a longitudinal study is needed to definitively show if marijuana is responsible for the brain changes and memory impairment. It is possible that the abnormal brain structures reveal a pre-existing vulnerability to marijuana abuse. But evidence that the younger a subject started using the drug the greater his brain abnormality indicates marijuana may be the cause, Smith said.

The groups in the study started using marijuana daily between 16 to 17 years of age for about three years. At the time of the study, they had been marijuana free for about two years. A total of 97 subjects participated, including matched groups of healthy controls, subjects with a marijuana use disorder, schizophrenia subjects with no history of substance use disorders, and schizophrenia subjects with a marijuana use disorder. The subjects who used marijuana did not abuse any other drugs.

Few studies have examined marijuana’s effect on the deep regions in the brain -- the ‘subcortical gray matter’ below the noodle-shaped cortex. The study also is unique in that it looked at the shapes of the striatum, globus pallidus and thalamus, structures in the subcortex that are critical for motivation and working memory.


The Marijuana and Schizophrenia Connection

Chronic use of marijuana may contribute to changes in brain structure that are associated with having schizophrenia, the Northwestern research shows. Of the 15 marijuana smokers who had schizophrenia in the study, 90 percent started heavily using the drug before they developed the mental disorder. Marijuana abuse has been linked to developing schizophrenia in prior research.

“The abuse of popular street drugs, such as marijuana, may have dangerous implications for young people who are developing or have developed mental disorders,” said co-senior study author John Csernansky, M.D., chair of psychiatry and behavioral sciences at Northwestern University Feinberg School of Medicine and Northwestern Memorial Hospital. “This paper is among the first to reveal that the use of marijuana may contribute to the changes in brain structure that have been associated with having schizophrenia.”

Chronic marijuana use could augment the underlying disease process associated with schizophrenia, Smith noted. “If someone has a family history of schizophrenia, they are increasing their risk of developing schizophrenia if they abuse marijuana,” he said.

While chronic marijuana smokers and chronic marijuana smokers with schizophrenia both had brain changes related to the drug, subjects with the mental disorder had greater deterioration in the thalamus. That structure is the communication hub of the brain and is critical for learning, memory and communications between brain regions. The brain regions examined in this study also affect motivation, which is already notably impaired in people with schizophrenia.

“A tremendous amount of addiction research has focused on brain regions traditionally connected with reward/aversion function, and thus motivation,” noted co-senior study author Hans Breiter, M.D., professor of psychiatry and behavioral sciences and director of the Warren Wright Adolescent Center at Feinberg and Northwestern Memorial. “This study very nicely extends the set of regions of concern to include those involved with working memory and higher level cognitive functions necessary for how well you organize your life and can work in society.”

“If you have schizophrenia and you frequently smoke marijuana, you may be at an increased risk for poor working memory, which predicts your everyday functioning,” Smith said.

The research was supported by grants R01 MH056584 and P50 MH071616 from the National Institute of Mental Health and grants P20 DA026002 and RO1 DA027804 from National Institute of Drug Abuse, all of the National Institutes of Health.

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Your working memory is basically your IQ, brehs. It's what gives Wall Street guys their ability to do the work they do. Attack your neurons and destroy your brains over an addiction (that's what it is), brehs.
 

Jhoon

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keep european american english majors working brehs
 

samtalksradio

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*Rolls Joint* What was this thread about again? Oh yeah, the establishment being afraid that weed legalization is catching on... gotta find a way to keep locking up black people and poor people since the war on drugs is almost finished... yeah studies like this will definitely stop people from smoking weed *lights up joint* fukk the establishment:pacspit:
 

godkiller

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*Rolls Joint* What was this thread about again? Oh yeah, the establishment being afraid that weed legalization is catching on... gotta find a way to keep locking up black people and poor people since the war on drugs is almost finished yeah studies like this will definitely stop people from smoking weed *lights up joint* fukk the establishment:pacspit:
:rudy:
This is a longitudinal medical study which looked at the long term cognitive and brain morphology effects of weed. I don't agree with the war on drugs but that issue respectfully has no bearing on whether weed is harmful. If weed destroys the brain, people have the right to know it. :ld:Destroying one's own health and prospects over a drug addiction and to spite medical researchers (or as you call them, the "establishment") does nothing but hurt a person. I'm a naturally intelligent dude so I don't need to read that weed makes your brain look like a schizophrenic person's. Just normal smoke is full of carcinogens. That's threat enough.
 

samtalksradio

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:rudy:
This is a longitudinal medical study which looked at the long term cognitive and brain morphology effects of weed. I don't agree with the war on drugs but that issue respectfully has no bearing on whether weed is harmful. If weed destroys the brain, people have the right to know it. :ld:Destroying one's own health and prospects over a drug addiction and to spite medical researchers (or as you call them, the "establishment") does nothing but hurt a person. I'm a naturally intelligent dude so I don't need to read that weed makes your brain look like a schizophrenic person's. Just normal smoke is full of carcinogens. That's threat enough.
W/E you say nikka *rolls another one* *inhales* :myman:
 

Dusty Bake Activate

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I'm curious as to whether there's any distinction in short-term anf long-term memory loss. My short-term memory is :flabbynsick:, but my long-term memory is godly.

For what it's worth, I went through a pretty intense and rigorous upper level biology curriculum full time at a good university with 3.4 GPA while working 30 hours a week living off campus and smoking weed 3, 4, 5 times or more per day, morning, noon, or night, if that's any motivation to you young weedheads.
 
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godkiller

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I'm curious as to whether there's any distinction in short-term anf long-term memory loss. My short-term memory is :flabbynsick:, but my long-term memory is godly.

For what it's worth, I went through a pretty intense and rigorous upper level biology curriculum full time at a good university with 3.4 GPA while working 30 hours a week and smoking weed 3, 4, 5 times or more per day, morning, noon, or night, if that's any motivation to you young weedheads.

Short term memory affects daily task orientation, which means it's probably as important. I won't comment on the details of your case because I don't know them. But it's not impossible to function while getting high, just like there coke addicts who can still do their jobs. But for every such coke addict there's another that falls into the abyss, never to be seen from again. Some people have more tolerance, others don't, but a person never really knows. This study merely shows some long term complications of memory and the brain. It doesn't say anything. People can make their own inferences from the data given.
 
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infamousred

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The younger the individuals were when they started chronically using marijuana, the more abnormally their brain regions were shaped, the study reports. The findings suggest that these regions related to memory may be more susceptible to the effects of the drug if abuse starts at an earlier age.
lmao no way!!! let's do one of these where they have them start drinking every day for 3 years(or any other drug for that matter), and see how fukked up their brains get at those ages. what a fukking waste of money. it's already been proven that it doesn't kill brain cells it just binds them together. when you research all the studies done on the drug you'll see it has far more good to it than bad. there was a paraplegic that couldn't stop having sezuires until he smoked some weed. they were trying to give him every drug in the pharmaceutical bin and he said if it wasn't for weed he wouldn't know what to do.
 

Mr. Somebody

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lmao no way!!! let's do one of these where they have them start drinking every day for 3 years(or any other drug for that matter), and see how fukked up their brains get at those ages. what a fukking waste of money. it's already been proven that it doesn't kill brain cells it just binds them together. when you research all the studies done on the drug you'll see it has far more good to it than bad. there was a paraplegic that couldn't stop having sezuires until he smoked some weed. they were trying to give him every drug in the pharmaceutical bin and he said if it wasn't for weed he wouldn't know what to do.

What disabling illness do you have, friend? :sitdown:
 

godkiller

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lmao no way!!! let's do one of these where they have them start drinking every day for 3 years(or any other drug for that matter), and see how fukked up their brains get at those ages. what a fukking waste of money.

Believe it or not but there are widespread misconceptions surrounding weed use and its effect on the brain/behavior. Some people don't think weed addiction can have similarly bad implications as alcholism and studies like these provide clarity. Moreover I have known people that smoke at least once at day so this study has implications for them.

it's already been proven that it doesn't kill brain cells it just binds them together. when you research all the studies done on the drug you'll see it has far more good to it than bad. there was a paraplegic that couldn't stop having sezuires until he smoked some weed. they were trying to give him every drug in the pharmaceutical bin and he said if it wasn't for weed he wouldn't know what to do.

I haven't read the study myself so I don't know the full details around what happens to the memory-related structures after weed use but the article speculates that neurons shrink. That might have been the prevailing explanation researchers theorized in discussion of the study. I think there is some validity for weed helping to manage chronic pain and illness.
 

Dusty Bake Activate

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Shortterm memory matters more than long term memory and they likely complement each other. It's not impossible to function while getting high, just like there are people who can come to work coked up and still do their jobs, but there are certainly short and long term complications to drug use.
The extent matters though. I've smoked a lot of weed in my life. I have a shytty short term memory. I can never remember things like where I put stuff in the house. But I can remember faces, words, incidents, etc. photographically, like it just happened. Whenever I reminisce with friends, they're always like "How do the fukk do you remember that?"

But my memory was always like that, before weed. I haven't noticed any appreciable difference post-weed.

But that's just me personally and I don't fit the study group criteria because I did it only once in a blue until I was about 18 or 19. I don't think I smoked daily til I was about 19. The study says they discovered that the younger you start, the more brain changes they see. It's not a good look to smoke weed daily when you're about 15-17, I would say, even without the research because your brain development is still so formative.
 

Consigliere

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Drinking turns your brain to mush, destroys your liver, and effects your judgement. We should re-criminalize it.
 
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