Myth: Marijuana use causes permanent short-term memory loss.
The Truth: Marijuana does cause short-term memory impairment but only when you are high. Just like how alcohol impairs your balance when you are drunk but not the rest of your life. Studies show that chronic smoking of marijuana does not produce major changes in general cognitive abilities like intelligence, memory and the ability to learn. Unfortunately there are marijuana users who help perpetuate this myth.
A study in Jamaica of 30 chronic users and 24 non-users investigated cognitive effects of long-term pot use (Bowman & Pihl 1973). The users smoked an average of 20 joints per day for at least 10 years. The testing took place in many environments from homes, huts to public places. The mobile approach ensured that even the most impaired individuals could participate. The study included many tests of reaction time, learning, perception and memory. The investigators determined that chronic marijuana consumption had no effect on cognitive abilities.
A more recent study looked at mental functioning of 1300 cannabis users in Baltimore over 11 years (Lyketsos; Garrett; Liang; Anthony 1999). The study used the Mini-Mental State Examination to examine the participants. There were no significant differences in cognitive decline between heavy users, light users, and nonusers of cannabis. Read it HERE.
Other studies show that the brain adapts to the acute memory effects (while you’re high) of cannabis. A laboratory experiment on rats and mice show that short-term memory in the rats dropped initially in the 35 day examination but recovered to pre-drug levels by the end. This study also shows some interesting stuff regarding cannabinoid effect of the hippocampus. Read it HERE. The acute short-term memory effect subsides after prolonged use. Long time marijuana users will also confirm these results.
Marijuana does not make you dumb or ruin your short-term memory. The myth was created and perpetuated by the anti-drug groups which continues to this day. If this myth were true 14% of Canada and 10% of the United States would live by a system of notes, photographs, and tattoos like the guy in Memento. As mentioned in the Amotivational Syndrome Myth, college students who smoke cannabis demonstrate comparable or even higher grades than their cannabis abstinent classmates, and are more likely to pursue a graduate degree (SOURCE).
- http://www.druglibrary.org/schaffer/hemp/medical/cannabisuseandcognitivedecline.htm
- http://en.wikipedia.org/wiki/Mini-mental_state_examination
- http://www.parl.gc.ca/37/1/parlbus/commbus/senate/com-e/ille-e/rep-e/summary-e.htm
- http://www.associatedcontent.com/article/107380/marijuanas_effects_on_shortterm_memory.html
- http://www.abovetheignorance.org/
- http://www3.interscience.wiley.com/journal/104524702/abstract?CRETRY=1&SRETRY=0
- http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1435998/
- Tolerance to the memory disruptive effects of cannabinoids involves adaptation by hippocampal neurons. Hampson, Robert E / Simeral, John D / Kelly, Erica J / Deadwyler, Sam A , Hippocampus, 13 (5), p.543-556, Jan 2003
- Bowman, M. & Pihl, R.O. 1973. Cannabis: Psychological effects of heavy use. A controlled study of intellectual functioning in chronic users of high potency cannabis. Psychopharmacologia Vol. 29(2): 159-170.
- Cannabis Use and Cognitive Decline in Persons Under 65 Years of Age, by C.G. Lyketsos; E. Garrett; K. Liang; J.C. Anthony; American Journal of Epidemiology, Vol 149 (No. 9) 1999, 794-800
Loopy Lettuce 
November 16, 2009 at 11:42 am
Very nice site!
November 23, 2009 at 9:20 am
NO, the MYTH is what you are saying about short term memory loss. I have experienced this first hand from my own usage and even worse among my partner. We don’t even smoke that much, but when we do, we suffer short term memory loss for way way longer than the high. I am talking weeks later. We get lazy.
Though I don’t believe occasional usage is any worse than occasional alcohol consumption, it does have adverse side affects.
One of my coworkers smokes it from the time he wakes up to when he goes to bed, at work, everywhere. He is a mess! He overreacts to everything, extremely forgetful, is in his mid-40’s and is living at home with mommy spending all his money on pot and kids toys, while driving on bald tires for months and had crashed his car and scooter so many times, his new scooter will no longer work, and his car is dilapidated (he thinks he was sold a lemon with the scooter, but it was brand new and wrecked it twice in first month). He looks so old for his age, very bad skin.
I share this with you because it is 3 people in my life (me included) who I have seen the side affects. It is too bad, because my partner and I don’t like drinking, but I am having to evaluate if smoking pot is worth our short term memory loss, our lethargy, and our diminished sex life due to less drives and our muscles feeling softer. I didn’t mention that we also make poorer food choices and get fat quickly on pot.
My partner suffers side affects worse than me, but he smokes it more, too. And then my coworker the most.
November 23, 2009 at 11:40 am
Thanks for the input MT.
To prove that one thing causes another you must remove all other possible causes. In the case of your co-worker, he is most likely depressed and using pot to cope. He probably uses toilet paper on a daily basis as well; why single out pot?
Your memory and laziness problems are not the result of marijuana use either. Studies prove this myth is false as well as the huge number of regular pot smokers who experience none of the symptoms you listed.
PS You must have a fucked up sex life because marijuana makes sex way better!
November 30, 2009 at 7:08 pm
Politicians are 10 years behind the times when it comes to hemp use. People have been fighting for a long time against marijuana and pot prohibition with some movement going on now. Still too slow for those caught up in the jail system for possessing a little weed. Our freedoms have been trampled on by folks who know nothing about how beautiful cannabis can be for someones life, if one learns how to grow cannabis. Keep up the good work.
April 28, 2010 at 2:05 am
i am still feeling a sort of emptiness in my head even 3 weeks later hope it will become alright soon .i am not a regular user but last time i had whisky and hash together and the effect was surprising …
hallucination as though i am in a sea and waves coming over me ,moving very fast like light or something,very forgetful i would have a conversation with my friend and would ask him what were we discussing 2-3 sec before
May 17, 2010 at 4:22 pm
first off, amazing site!! ive been stuck here reading everything for like an hour. whoever was crying about how smoking effects your short-term memory loss obviously never had a very good one to begin with. i smoke everyday, and i have a 3.8 GPA in college. if anything has improved my life, ive met some of my closest friends through smoking. sure i get lazy after i smoke but who wants to do chores, homework or anything like that when youre drunk i know i dont. ive never been hurt through smoking or anything else that people cry about due to pot. best thing in the world is waking up with a romping hangover and you cant even get out of bed, then smoking a blunt and feeling like you can run a 10k. SMOKING ROCKS AND SHOULD BE LEGAL.
May 10, 2011 at 10:16 pm
@ngust HAHAHAAH you said he probably uses toilet paper thats hella funny and yea sex is way better when u loaded this fool must be smoking trees from a male plant lol but i recently quit burning because my parents drug test me (even though they cant seem to realize that i do 100% of my homework and 100% of my chores and i used to burn MULTIPLE TIMES EVERY SINGLE DAY) so now i fucks wit pills, does anyone know if those make you have short term memory loss? cuz i know FOR SURE that weed does lol i cant remember shit anymore.
May 23, 2011 at 8:26 pm
Twenty joints a day? Oh, among 24 users. Unclear as written. 20 joints a day would leave me and most humans unable to get off the floor. Even an average of one a day could do it for some of the grade A medical pot out there.
Sex life diminishing? Now that seems odd. I get very horny and sensuous when stoned.
I do notice that my head feels “light” the next day and I have to push harder to really focus. When I am stoned I can read but it is like every page seems too fraught with meaning to get much reading done.
September 8, 2011 at 7:37 pm
Thank you so much for this article, it’ll do a lot to curb my worrying about this sort of thing.
Most other articles I could find defending the same position, unfortunately, actually did more to unease, than to convince the reader as to the credibility of the argument since they often sounded something like: “no way man! me and my roommate smoke all the time! and we feel fine! fuck the government!” And moreover, they gave only one citation (if any) of any real study that agreed with them.
You’ve got yourself a convincing argument here.
October 19, 2011 at 11:30 pm
i have been smoking everyday now for the last 4 years and I can tell you that my memory sucks now and i am a lot dumber.
For the past year and a half I have been only smoking at night starting around 8pm then I would go to bed at like 1-2am. I would smoke like 4 times a night. Its a lot but its not like im high all day and im never “sober” . I never smoke before work (i would be fired in a heartbeat because of how obvious and incredibly stupid i would be. ) so im not high for the majority of the day.
There is no question in my mind that weed is negatively affecting my memory and is the sole reason that i feel “dumber”
To the people saying that it doesnt do anything and that it actually improves your brain and capacity to learn… It has differnet affects on different people it made one of my college buddies smarter or whatever when he smoked and he can get away with doing it every day and still functioning perfectly fine.
I, on the other hand, am not so fortunate. I am sitting here now with 1 more hit in my bowl and no weed left. I was going to pick some up today but I was talking with my friend about how its ruining my performance at work and my memory in general, so now i think i am just going to quit. starting tomorrow.
But i may also just try that nasal spray stuff first…. i give into temptation very easily
December 13, 2011 at 4:03 pm
very well put. thats the only way i can usually tell when someone is stoned. The only really big problem i have seen with it is getting alot of jobs and keeping your plans. When i used to smoke, I would put off alot of plans because i would forget until the last minute and by the time i would remember i would be too high to want to do it. I do not mind it at all, it just has certain effects on a person and i wish marijuana smokers would notice that they do this.
December 13, 2011 at 4:07 pm
oh, but it is harder on your lungs than cigarettes. i quit both in the last few years and have noticed how much healthier and more energetic i am. I dont think it should be illegal if sigarettes are legal, i just think that like alot of things, its just another bad habbit.
March 4, 2012 at 11:08 am
chronic…
[…]Marijuana Myth – Short-Term Memory Loss « Loopy Lettuce[…]…
May 29, 2012 at 6:07 pm
People saying weed makes them dumb and slowed down are probably either irresponsible people or have something going on upstairs that they can’t focus on other things besides there own thoughts. I’ve seen many sides to marijuana use, You got michael phelps, olympic swimmer won gold medals smokes pot. On the other side I know ppl that don’t work and are living off the gov’t that still smokes pot. Difference between people like Mr phelps and Mr Anonymous, Mr Anonymous doesn’t care to take care of hiself. He’s a wreck, always wants to play victim instead of standing on his own two feet. Wants everything to come easy for him.
If you blame being high for you not doing anything I really think it’s cuz people are lazy, and not just people my dog can sleep for an entire day. If I was with my girl sober I wouldn’t be constantly wanting to go climb mountains and sky dive. I’d much rather relax on the couch with her.
Now I do get tired when I smoke and it starts to wear off. But then I eat or sleep and I feel ok. If you feel so lightheaded the day after you get high that you can’t think…then maybe you should quit, but to be honest you just sound like a really sensitive person. If you’re so vulnerable maybe you should either quit or learn to steer your vessel. And remember sometimes you gotta steer and sometimes you gotta float. Either way happy hunting.
May 29, 2012 at 9:36 pm
Great input. “Steer your vessel”, well said.
June 21, 2012 at 6:13 pm
People are ridiculous with their lies and misinformation. Pot will affect your short term memory, so I wouldn’t recommend getting stoned and studying since you will probably forget a decent amount of the stuff you studied when you were high, so it’d be a waste of studying time. It does NOT ruin your life unless your life is already headed in that direction. Pot won’t fix your already messed up life. Sorry.
July 23, 2012 at 6:18 pm
its while your stoned that you feel the effects.you know if it was like every plant than you could find the strain that best suits you.like coke or pesi or water.How can they make something elegal that they never made.Why don’t they focus on the chemicals they’ve made. but like the guy said its the people that don’t know when to steer or float that grow up and make up all theses lies but hey if it makes you feel better(cognitive dissidence)
but hey if it makes us feel better( personal freedom) than whats your problem. you feel good that you quit, because you feel you should steer that direction(yet you can’t steer a stone)And we feel good to float.get off your high self-centered horse or should I say low.
July 30, 2012 at 7:41 am
The study disproves itself when it starts off by making the statement, “The Truth: Marijuana does cause short-term memory impairment but only when you are high.” For people that are high on a regular basis, then obviously they suffer from short term memory impairment regularly, which affects long term memory, which affects learning ability. The way they worded the study was intended to lead people astray. What it means is, whenever you are high, your ability to learn is affected, and whenever you are not, it is not. If you are high for several hours a day on a regular basis, then you are at a huge disadvantage over someone who isn’t high. The study was obviously done by someone with extreme biases for trying to prove marijuana use is fine. I doubt that any serious people in the scientific community give either of those studies any credence.
July 30, 2012 at 9:37 am
Marijuana definitely affects your memory while you are high. The myth is regarding long term damage to your short term memory.
July 30, 2012 at 9:49 am
Ed, you are correct about the fact that if you are high all the time your are not at your best as far as learning and memory are concerned. However a tolerance develops as it does with alcohol, caffeine and other drugs. A long term user experiences less impairment and for shorter periods of time.
If you spend your whole life under the influence of marijuana then of course you will not be at your best. If you were drunk 24/7 you would not be a star student would you? That is not the argument here. This myth is related to long term damage to an individual’s short term memory as a result of marijuana use and the myth is completely false.
August 14, 2012 at 11:10 pm
Another thing is that, from my own introspection, perhaps, it is the side effects of laziness and effortlessness, that leads one’s lifestyle into repitious and monotonous activities that do not stimulate you enough to even care to remember, eventually these meals and activities blend together and you become depressed. (this is also a side effect of having an unsatisfying job) If you are suffering from short term memory loss as I have, my suggestion is these few steps :
(1)do something stimulating, such as read a book rather than watch t.v.
(2) have some alternation in your schedule, brush your teeth with your left hand, be aware of your mechanic actions
(3)jump out of your comfort zones, speak up, start a conversation, unplug your computer, give your mind some disciplinary challenges
(4) exercise, such as jogging, studies show it actually activates your brain cells, hence making you more attentive and aware
(5)do something you have always wanted to do but never gave the time to do it
(6) Do all of these things without smoking, and you will remember
August 23, 2012 at 7:13 am
Save from re-iterating the post above mine, I can’t place more emphasis on mentally asserting a use of your memory. It hasn’t left, you just aren’t using it in such a manner that you had before you smoked. Transpired events become hazy and actions instinctual as opposed to planned and articulated. Reading and exercising are key. If you smoke for years (I smoked for about 5, on a regular basis) cannabis becomes copula with everything you do, so as opposed to an actual substance addiction it becomes a lifestyle addiction. The treachery is that the changes are so subtle you feel defeated, hence the depression (cannabis may not be a depressant in and of itself in most cases, however it is a catalyst). As to long term effects; nothing is long term unless you let it be. Take action and convince yourself you don’t need a crutch. I quit for this issue alone, I was tired of never having all of myself present when I needed me. Aspire to learn something new every day and stop smoking if you think it will help. On a side note, why smoke to feel something different when you’re high every day? Sobriety becomes new and different haha.
August 23, 2012 at 10:41 pm
Nice post. Its true about sobriety being different. If you are high all the time you get complacent and when you take a break sobriety puts you in a different mindset. Its kind of neat to try not being high once in a while to mix it up.
For those out there who are having problems, stop smoking pot. On the other hand if its working out for you then keep on truckin’.
November 21, 2012 at 10:55 am
Anyone ever thought that we attribute bad people with pot because people that are willing to do illegal things are the ones doing pot. Make pot legal and law abiding citizens will start to do it more, meaning this perception will diminish or disappear. (im not saying all pot users are criminals in other areas of their life, just on average it seems that way now because it is illegal.)
December 19, 2012 at 6:48 am
After smoking a few joints, the idea of inventing a new test came into my mind… So, right off the bat, smoking pot creates thoughtfulness; a doorway into “other” parts of the mind so to speak.
Find me two or three IFR rated Pilots who is willing to Smoke a joint and then fly in an airplane simulator in simulated IMC conditions before getting high. We will record the flight.
Next, get them high and let them try the same while stoned.
At certain intervals after getting high they shall fly the same route and shoot the same approaches after smoking as they did before and during.
We will have them shoot a couple of ILS approaches during each test flight and will fail an engine during an approach.
After the test lets post the tracking results and response times. The results will show the effects of pot on every aspect of fine motor skills, memory, response times, cognitive function… everything.
Until someone performs this test we will never surely know if smoking pot messes people up. It will be a mystery only to toy with the minds of those smoking pot especially while stoned.
February 5, 2013 at 5:29 am
Smoked weed every day for 2 years. used to be extremely smart, hated the way the world worked, society nd people in general, so i escaped with it
Now my memomry is non existent, i’m so dumb I often laugh at myself
When everyone first starts smoking they believe this “weeds fine, nothing wrong with it” bullshit “Better for you than alcohol” and because of that people abuse it hard. I’ve done all sorts of drugs and I myself, nd a few close mates would say that weeds the worst out of all of them
April 9, 2013 at 10:45 am
This is bullshit. People will believe what they want to believe, thus interpret this material to be true and spread false rumors.
Here are my sources: http://www.health.gov.au/internet/main/publishing.nsf/Content/health-pubs-drug-cannab2-ch74.htm
http://informahealthcare.com/doi/abs/10.3109/10826087709022166?journalCode=sum
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2269704/
Cannabis and Cognitive Functioning By Nadia Solowij
Click to access Solowij.pdf
http://www.nature.com/news/2010/101001/full/news.2010.508.html
http://www.cbsnews.com/8301-205_162-57389778/scientists-explain-marijuana-short-term-memory-loss/
May 8, 2013 at 9:27 am
90% of the shit that comes from the United States government in regards to marijuana is bullshit. Get your heads out of your asses.
April 17, 2014 at 3:17 pm
The only REAL problem I consistently see with Users who experience negative symptoms is lack of personal responsibility. No offence but if I feel lazy after vaporizing bud and choose not to leave the couch, that’s still MY choice.
I can be a very anxious person, and I am constantly in thought(often negitave). Weather it be about lifes problems or anything else you can imagine. I also have a hard time controlling these thoughts and staying task oriented. Through-out grade school and high school I was always struggling to pay attention in class, and for the most part didn’t get very good grades. Therapists told me I had A.D.D. They gave me Ritalin (didn’t help), and then Adderall (still no Improvement).
I smoked pot a hand-full of times during the middle school, and high school years because it was cool, and it made me feel like a bad ass for breaking the law. I decided it was bad for me due to pressure from the social stigma, and False information fed to me buy my educators. I didn’t touch the stuff again…. Until…
About 4 years ago I met the love of my life. She was into pot (smoked on occasion), but at that point I was very against it(social Stigma). I wanted her to quit all together at first, but eventually decided as long as she didn’t use it constantly it was ok. My curiosity soon kicked in and I found my self trying it here and there once again. I really liked the feeling of being high. After a while I started to notice that when I was smoking my thought process would slow down, and would feel (oddly enough) “clear headed”. I experimented with using while doing various things throughout the next few years. I have found that it can help me focus, and most importantly it keeps me level headed in times of high stress. Before long I become a daily user, I purchased a Vaporizer and would use a small amount 2-3 times a day. I had never felt so clear headed, and productive in my whole life. I wish my state would allow me a Medical card for it so I could narrow down which strains seems to help the most. which leads me to another point. Until its regulated better most users have NO IDEA what they are smoking. cannabis is HIGHLY variable in its effects because there are SO many different strains.
Currently I am not using because of the risks involved with employment. I have noticed NO change in my memory. The only change I observed since I stopped is that my thoughts once again are running rampant and making daily life difficult in terms of being productive.
I believe Cannabis if used correctly can be HIGHLY therapeutic and yes, Harmless. It sucks that so many users who have misused the drug blame it for problems they most likely already had, I.E. Personal responsibility. Hope to see this movement pick up speed. I would love to see studies eventually find just how many uses this plant has aside from the ones were already aware of.
July 23, 2014 at 9:08 pm
Then look elsewhere, there have been many studies done by independent, foreign nations, etc. that all came up with the same result. Smoking pot causes permanent short term memory loss. The psychoactive ingredient of marijuana is tetrahydrocannabinol (THC). All these studies have found that the compound (THC) weakens the connections, or synapses, between neurons in the hippocampus, a structure that is crucial for memory formation. Over time these neurons do not function as they originally did leading to short term memory loss and lack of concentration. I’ve done studies on this topic myself….so it is what it is. You want to smoke pot, I have no problem. What to legalize it, whatever, but don’t lie to others to promote your beliefs.
August 28, 2014 at 4:05 pm
I appreciate your efforts in this study. However let me tell you something and this is coming from a long term daily cannabis user (10 years and 3 months), cannabis is severly detrimental to the brain and can causes permanent memory loss along witb reduction in IQ levels and there are many researches (reliable researches witb spot-on methodology) that will back-up this statement. First of all the tests done on people in jamaica i woulbt necessarily count as the stuff they smoke is not the same as the high grade stuff (skunk , kush, wotever u name it) and will causes these deficits the high grade cannabis does but at mucb linger duration and are considered safer in that sense (but still dangerous).
From my experience n many many of my friends who have smoked as much as i did, some even only for 2 or 3 years have experience severe memory , concentration and poor academic performance that they had to eventually quit the habit. Some of them reported full recovert and some only partial. There are online cannabis addiction forums where u can read stories of people who have abstained for months after years of regular consumption and emphasize on the harmful effects of this ‘not so benign’ drug and i mean thousands. I personally was the top of my class in college and considered one of the brightest student in universoty have lost most of my intellectual abilities as well as memory , concentration etc. Cannabis use impairs verbal memory, short term memory, working memory, recalling of information. It can cause some sort of brocas aphasia indicating lesions or dysfunction in the cerebral cortex and has been proven in a recent research (published december 2013) to cause atrophy in the hippocampus and amygdala. These are structures involved in memory, motivation and regulating emotions. In other words it has been shown in functional MRI scans of heavy marijuana users to cause 40 % reduction in these structures which are an integral part of cognition.
Not to mention psychiatric illness that have been trigerred by heavy marijuana consumption or even moderate consumption on some occasions.
So please think of the message you are sending the youth when you publish such an inaccurate article with such unreliable reseach study results.
I hope everyone reading this comprehends and acknowledges how much toxic cannabis is to the brain. First few years or months are fun and its always nice to zone out every once in a while but it can turn into a living hell robbing you of the simplest joys of life and turning some1 with so mucb potential into a miserable useless Bum
I hope you consider your opinion on the topic as i am more than qualified to make such a judgement about this particular drug.
November 24, 2014 at 9:53 pm
MT your not the only one with short term memory loss. I also when I smoke pot get that but it goes away when the “high” passes. My BF laughed at first but then was concerned because I explained how I felt. I decided to stop because its not a very fun experience.
August 11, 2016 at 1:45 am
I’ve never been a heavy smoker, but 4 months after I stopped smoking I began to have short term memory problems. I understand it can be from stress, or depression and I am very stressed right now but pot is the only drug I’ve ever taken and it’s just got me worried.
June 9, 2018 at 11:06 pm
What was this article about again?