Marijuana’s Impact On Brain Function “Minimal,” New Study Says
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July 28, 2009
[Editor's note: This post is excerpted from this week's forthcoming NORML weekly media advisory. To have NORML's media advisories delivered straight to your in-box, sign up for NORML's free e-zine here.]The consumption of cannabis, even long-term, has a “minimal” impact on brain function, according to a systematic literature review just published online by the journal Psychological Medicine.
An international team of investigators from the United Kingdom, Spain, Brazil, Australia, and Switzerland conducted a systematic review of the effects of cannabis on brain structure and function.
Authors wrote, “We reviewed literature reporting neuroimaging studies of chronic or acute cannabis use published up until January 2009. … Sixty-six studies were identified, of which 41 met the inclusion criteria. Thirty-three were functional (SPECT/PET/fMRI) and eight structural (volumetric/DTI) imaging studies. … Only three of the structural imaging studies found differences between users and controls.”
Investigators concluded, “Minimal evidence of major effects of cannabis on brain structure has been reported,” noting that marijuana users and controls perform similarly on cognitive tasks.
According to a 2001 study published in the journal Archives of General Psychiatry, long-term cannabis smokers who abstained from pot for one week “showed virtually no significant differences from control subjects (those who had smoked marijuana less than 50 times in their lives) on a battery of 10 neuropsychological tests.” Investigators added, “Former heavy users, who had consumed little or no cannabis in the three months before testing, [also] showed no significant differences from control subjects on any of these tests on any of the testing days.”
121 Responses to “Marijuana’s Impact On Brain Function “Minimal,” New Study Says”
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As a long time smoker, I can only speak of how it affected me. My once, almost photographic memory went down to a fog after three years of daily smoking. Ten years ago I stopped cold turkey after daily smoking for 15 years, and it’s taken daily supplements of fish oil o bring me back to about 75%.
During this bout with weed, I stopped maturing emotionally and settled for stuff that I didn’t settle for both before and since. It’s like I was stuck in a place in life and didn’t realize it until I was no longer under the influence. I lost a good 15 years of my life, sitting on the couch with my head in a fog.
I definitely do not miss it.
Debi Davis
I think that from the looks of it this was a sound experiment. Your comparing the structure of two Brains one that is high versus one that isn’t. If this is true then as we all know well enough Marijuana is nothing but a plant just like Tobacco is but has FAR LESS dangers than Tobacco. With that said, Legalize it already. Geez. Just cause we don’t grow the shit don’t mean we can legalize it and tax it. Politicians need to realize how much revenue this could potentially bring in.
RE: #102 Steven,
- It’s not really about cannabis vs. tobacco,
it’s about the right to utilize a God-Given plant,
whether it’s cannabis, tobacco or basidiomycetes…
- The method of its administration, when and
how often it’s partaken of, how it is grown,
what its fertilized with… are stronger determinants
of its relative danger(s) / safety…
- Every factor considered, all of the above ought
to be allowed, (never prohibited), be taxed and
regulated if sold / dispensed in a retail-manner;
- Free for one to grow and utilize for one’s self,
(personal responsibility applies here…)
never blame the plant-compounds / plants for
personal-stupidity…
- Some politicians think it’s a “bad idea” to
garner revenue from what they see as possibly
“dangerous”, “addictive” vices, merely because
of desperate economic-times.
- HOWEVER, bringing these “vices” ABOVE-GROUND
allows the “dangers” to be managed more effectively
and minimized…while availing revenue-streams
to do so…
Debi,I am not sure where you are coming from. I have smoked marijuana virtually every day for 35 years (I’m 52), have held work as a programmer, technical support technician for a larger manufacturer and an IT manager for a White Plains security and never have had my smoking cause me ANY cognitive issues. You might consider a functional MRI to make sure that your frontal lobes are fully functional. Do you drink? How does that affect your Photographic Memory? Why deny me my vaporizer? I don’t come and spit in your Merlot. Besides, why let a few facts get in the way of your anecdote?
I will find a way to make this plant legal somehow i will not give up the fight i have been smoking a long time now and i know the real deal they are making me go to rehab for it now have not toked in a month i feel no withdraw but my body’s ache’s and pains have returned m.j.is a nice(alt)to the nasty pills they try to shove in my mouth and i liked the no side effect cept getting hungry sometimes jesus the gov. is just down right evil the only green they know is a stupid piece of paper F*** them i won’t do what they tell me!(rage against the machine:)
This studddy was goo d two weed couse it proves that I am not stuped. I now am over 50 y/o and I smoked cannabis offand on my hole life and I have quit a lott oftimes for work and whem I got kids and my wife sad “stopthatsmoking” I held lots andlots of good jobs and I work good. So sometimes I sreel smoke and sometimes I dint and I isok and have good kids that dint no I abide in it. Thankyou for putting this studdey on my pc and I hop that the govermenit getsit and leves people likeus a lone. Rock on>
me
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weed in my mind ye weed in my brain , i wana get high leagalize it
my story…
bye bye love caz
when i was 11 years old i first tried weed it was pritti tasty you see and now i smoke it evryday through a bong or pipe or jus spliff either way i am high i am in school writing this rite now in ict i smoke tha dutch dutch stuff iz gd shit , i am going to try and get my friend birdy to do weed evry day in his relient robin and i wil race him in mine when i am high and he is high and it will be gd shit and then foyce will come along on a moped and get knocked of coz he is to high to ride it… it will be some quality shit and will be funny as… i am writing this because i am bored as i am going to get my mum high 2nite and feed my lil sis and bruv weed on their b days jus so they can be happy and lil bruva hu isnt even 1 yet weed and am gona make hi mdo a lung and then give the ol wolner boi a spliff on the go and go for a spin down the orad on a pedle and pop when im high and beat birdy in his relient robin.
The biggest risk marijuana carries with it, is getting caught. Legalize the shit already, its just stupid, im in college and i do all my shit, deans list all day. But i get bored as hell and what better thing to do than spark up, i love the shit its the ultimate boredom killer.
Put plainly, if you smoke marijuana your probably not going to end up going crazy, or turning into a drug addict, or join a gang.
But you will be perfectly ok with sitting on the couch doing absolutely nothing for hours at a time.
And you might also get arrested for it
These are the real only dangers to marijuana.
Well said, Marijuana has very little effect on over all cognition and brain function when normal users are compared to non users. Obviously there are some tendencies to be lazier or more lethargic but for some people that might actually be a good thing. As for some of the e other commenters talking about how Marijuana is a gateway drug and how it makes you want to use other controlled substances is complete garbage. The gateway argument is propagated by conservative people who view marijuana in such a negative light they equate its as tantamount to cocaine, speed, or crack use. Often times these are the same people who have never used marijuana and are ignorant on the subject in general. For more info on marijuana check out http://mrbuds.com .
All in all marijuana is a positive substance that causes more good than harm out of every controlled substance out there. LEGALIZE IT!!!
Its nice to see so much information on legalization showing up in all forms online. America is closer than ever to seeing the drug war overturned.
NIXON STARTED THE WAR ON DRUGS
NIXON IS HATED BY EVERYONE
WHY DON’T PEOPLE HATE THE WAR ON DRUGS?
oh they’re sheep, my baaaaaaaaahd
also
cannabis IS a gateway drug in the sense that, once you start smoking it, you hang around with other smokers
and people who are usually on HARD drugs usually smoke the ganja cos it helps with comedowns/feels good man and has no effect
then PEER PRESSURE OMGFGJFGHINPO;SNK
yeah, gateway my arse
Marijuana’s Impact On Brain Function Minimal – New Study Says…
The consumption of cannabis, even long-term, has a “minimal” impact on brain function, according to a systematic literature review just published online by the journal Psychological Medicine….
I disagree with some points and agree with others. After using marijuana for 6 years and then being marijuana free for the past 2 years, I can confidently say that marijuana does, (for some people) make you stupid. Iv done some brief research on the topic of ‘How does marijuana affect the brain’ and have come by some interesting points. People have stated that marijuana has made them smarter; it helps people with ADD to focus better; it makes people think more clearly when high; brings out ‘creativeness’ in some people. These are very good opinions, considering that everybody infact does react differently to this substance. As a user for 6 years, marijuana has truely impacted my brain for the worst. I have ADD, and weed made it worse. I never got good grade before I started using and I still didn’t after I started using. I could never remember any information that was taught to me in school, and I could never remember what i did the day prior to the present! Dont hold me to this, but I have heard that “the state of mind that you are most confortable in, will positively impact your performance in most activities that you do.” Therefore, if you are most comfortable in the ‘high’ state of mind, then you will perform best while you are in that state of mind. It’s a very logical opinion. Here again, everybody is different. If you study high, and take the test high, then you might get good grades. Iv tried it years ago and it did not work for me. Try it for yourself and see the outcome. On another note, marijuana does indeed help you to connect with other people that you normally wouldn’t find yourself connecting with. I dont know if it is due to the fact that two people want to get high and put their thoughts and opinions aside for the 10 min. of smoking or what, but i have definatly found myself in that situation more than once. After being drug free for two years it is safe for ME to say that I have definatly changed for the better. I am smarter now, more open minded and I have the will to WANT to learn. Before, when I use to smoke I had no desire what so ever to learn or do anything that involved education. Lets just say I learned the hard way. Now I am in college, able to read a book and interpret it, able to find out the main idea of a text, and able to do many other things that I wasn’t capable of doing before. Enough about me though, experiment for yourself what using and not using is like, and then analyze the results. You might be amazed, or you might be the same. Give it a shot, you’ve got nothing to lose.
I agree that people react differently to marijuana. I believe that it depends on the person and your mind set. I didn’t do that well in school but i noticed that when i started toking, my grades increased. I would actually pay attention to classes i usually found boring. Doing lame things were less, lame. Going into work i knew what i had to get stuff done and I was more efficient. I would have months where i didn’t smoke and everything became like it was before, boring and tedious. Assignments were less of a drag to do when high, also i was more creative. This is all personal experience so might not be for everyone.
I have found no harm and the only reason people don’t want to legalize it is cuz of money.
What is a dollar really? It’s just a piece of paper that the man tricks people into believing it has value, when really it holds no value and is only imaginary just so the gov can keep control.
ALright i have been a chronic smoker for 5 years now and I do know it has effects on me.. i have quit a couple times usually a 2 week period and i can say after this 2 week period i felt more motivated and less distracted.. i kept smoking afterwards of course i like how it makes me feel:) i can also say it is addictive i dont care how many people say its not ive probably smoked more than them beings as i smoke about 4 grams a day everyday. the side affects of the addiction are loss of appetite, (happened everytime i quit)depression, and definatly insomnia. Dont try and argue this with someone who has gone through it many times:) of course i still smoke. im recently goin 6 days sober because of a possesion charge and i have slept for probably 14 or so hours, ya not good. it is addictive it is a drug. im not saying it should be illegal like many have said alchohal and tobacco are both legal and deadly:) i had to post this, im tired of other potheads (me saying “other” because i am one:)literally lying to themselves and other people that its not addictive and that there is no harm. i personally wake up everyday coughing with flem and you people are trying to tell me thats supposedly not bad for you? its something that makes me laugh i dont defend it at all our kids probably shouldnt do it and people just need to realize ITS A DRUG! ps i gaurantee i can take a bigger bong rip than the person whos gonna try and argue with me saying pots good:)
[...] Can't be arsed to re-read the study, but here is a place for you to start if you wish. http://blog.norml.org/2009/07/28/mar…ew-study-says/ ____________________________ "War is a racket. It always has been. It is possibly the [...]
Most of you have missed an important point. The study finds no differences in subjects after the have quit using for a week. Those who use regularly may never reach this one week abstinence period are living with some effects of marijuana on a daily basis. The most significant effect will be a reduced ability to learn and remember. While this may not be an issue if you smoke occasionally, if you smoke daily for months or years, your learning over time will be significantly delayed compared to non-users. Our learning as teens is obviously very important. Missing months of years of school will have a serious impact on later achievement. Even for adults, failure to learn for years at at time will affect their quality of life compared to their non-using peers.
legalize it, ciggerets are alot worse. Zero people a year die from marijuana, billions die from ciggs