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Effects of marijuana on the brain (INFOGRAPHIC)

Short AND long term effects of MJ on the brain

Marijuana is known to affect functional parts of the brain when you are high. But marijuana does not only affect the brain for a shorter period of time. While some effects are completely reversible, it can also change the way our brain works. Marijuana can also impair the brain’s development in teenagers. And what most stoners don’t want to hear is:

The scary thing is, some of these changes may be permanent, or at least long-lasting.

Effects of marijuana on the brain (INFOGRAPHIC)

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How does marijuana affect the brain?

The THC from marijuana affects the hippocampus (the brain region responsible for memory formation). Brains that are influenced by marijuana during neonatal development, after birth (through breast milk) or during adolescence have significantly lowered learning/memory capacities. These changes are connected to the structural and functional changes THC causes in the hippocampus.

Long-term marijuana effects on IQ

Studies also suggest that initiating marijuana use in adolescence and continuing with chronic and persistent use is associated with a loss of an average 8 IQ points. In that same study, the subjects that measured lower IQ after heavy and continuous marijuana use did not recover the lost IQ points. Heavy use in adulthood did not lead to the same results and mature marijuana smokers had no significant changes in their IQ.

Other neurological side effects of marijuana

The basal ganglia, cerebellum and hippocampus are not the only brain regions that marijuana affects. Here are more brain centers whose function is changed under the influence of THC:

  1. The cerebral cortex – associated with higher cognitive functions
  2. The nucleus accumbens – which is the ‘reward center’ of the brain
  3. The hypothalamus – responsible for regulation of the homeostatic functions
  4. The amygdala – a gland which regulates emotional responses and fears
  5. The spinal cord – associated with peripheral sensations on the body (pain)
  6. The brain stem – which controls motor functions, sleep and sexual arousal
  7. The nucleus of the solitary tract – associated with visceral sensations (nausea and vomiting)

Marijuana effects on the brain questions

Like our infographic? Don’t like it? Feel free to SHARE it with your friends on other networks. Or comment here. We’d like to hear from you.

Also, if you have any questions regarding marijuana’s side effects on the brain, central nervous system, nerves, etc., we welcome you to post your questions in the section below. We try to provide a personal and prompt response to all legitimate inquiries.

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25 Responses to “Effects of marijuana on the brain (INFOGRAPHIC)
2:44 am March 14th, 2017

I am a public middle school teacher. I have many many students who are using marijuana and think it’s ok to get high. I was wondering if you might be able to send me one of the poster above for my classroom. If I can get through to one student it will be worth it.
Thank you so much,

Lydia @ Addiction Blog
2:42 pm March 31st, 2017

Hi Cait. We really appreciated that you find our marijuana infographics educational. I send you a private e-mail from the pdf files in order to print them out.

7:04 pm May 9th, 2017

I would love to have a copy of this poster. I am a nurse at a high school and feel this would be very educational for some of my students.

Lydia @ Addiction Blog
2:58 pm May 11th, 2017

Hi Heidi. Thank you for your interest in our infographics. I send you all our marijuana infographics in a private e-mail. Hope your students will find them educational.

6:40 pm August 22nd, 2017

I too would like a copy of the poster. It would help my students. Thank you

Lydia @ Addiction Blog
5:08 pm August 23rd, 2017

Hi Frank. Sure! I’ve send you a pdf file from this infographic via e-mail. Hope your students will find this infographic helpful!

6:50 am January 11th, 2018

Could you post your sources? From my own scholastic research, I find most of this questionable at best. There is scant research on these matters so much of this (lethal overdoses and long-term effects) is speculative and possibly fear mongering. If these are being used for educational purposes, the least you all could do is post your sources.

Lydia @ Addiction Blog
3:56 pm January 23rd, 2018

Hi Marisa. There are many reference sources for the creation of this infographic, and because of this fact they are not posted here. However, we send them via e-mail to everyone who is looking for them. So, they are on the way to your private e-mail. Best.

3:59 am February 12th, 2018

Hello, I used to be addicted to weed and other drugs, but I’ve realised how much it harms me and decided stopping it forever. I also have a friend who is chronically addicted to it ( He can’t stop smoking for a week without relapsing the following days due to emotional and psychological withdrawals. Is there any chance I could have a copy of the posters and show him how much it affects him? I’d be appreciated. Thank you.

Lydia @ Addiction Blog
11:17 am February 13th, 2018

Hi Roddi. Yes, you can print out this infographic.

9:30 pm May 22nd, 2018

The infographics are great! Could you email me a list of the sources so I can delve further? Thanks!

Lydia @ Addiction Blog
12:01 pm May 30th, 2018

Hi Jennifer. We are glad that you liked our infographic. I’ve send you the reference sources via email. Best!

12:20 am June 4th, 2018

I would also appreciate a copy of your resources please. Thank you!

Lydia @ Addiction Blog
12:37 pm June 6th, 2018

Hi Janine. Of course! I’ve send them via e-mail. Hope the resources will help you!

4:32 am July 10th, 2018

Hi! This is wonderful information. I am a substance abuse counselor for Adolescent Boys in residential treatment. I would love to have one of these posters!

Lydia @ Addiction Blog
11:03 am July 10th, 2018

Hi Rebeca. The infographics are completely free of charge. Download them, and print them out!

10:35 pm September 25th, 2018

I will live to have copies of the informative poster as I will be helpful for me as well as my patients

Lydia @ Addiction Blog
6:08 pm September 28th, 2018

Hi Drsushant. Feel free to download and print out our infographic. There are completely free of charge.

5:24 am October 7th, 2018

Hi, where exactly are you drawing these statistics from? Not able to find any numbers involved either. Is this based off of conducted research? And from where!? Is this 10% of people who smoke marijuana chronically or 1%? 95%? A little confused with this overall poster. Please send me the sources. Always willing to learn more of science-backed info 🙂

11:36 pm October 24th, 2018

Wow. I had no idea that there was a recorded incident of lethal ingestion of marijuana. Can you share your resource on that? How many people have overdosed? Do you have anymore details? One of the reasons marijuana was seen as a safer drug is because you can’t inhale enough to have a lethal overdose. Obviously you’ve showed all those scientist wrong! Can’t wait to read your research! Thanks so much!

Deborah E
11:28 pm October 27th, 2018

I I think if you added a section where you defended smoking marijuana then explained why that line of thinking is incorrect but you have to give real facts and studies with all the credit of who did the study, paid for it etc… YOU Have to have truth in journalism above all else!!!

12:17 pm October 28th, 2018

Hello Deborah.

Sure. Studies are mainly on animal, and the ratio of lethal dose to effective dose is quite large. Fatal doses are unlikely….but technically possible. You can find more info on marijuana toxicity here:

7:04 pm November 13th, 2018

Hello Meghan. We base all our research on NIDA and/or research published in medical journals. In this case, the particular statistics you’re speaking of can be referenced here, although some studies claim addiction incidence of marijuana up to 30% of user!:

12:19 am January 17th, 2019

I want to ask a few questions abouts Weed’s effects on the brain, can I get an email?

Lydia @ Addiction Blog
10:28 am January 17th, 2019

Hi Jack. Yes you can. Send us your question at

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