The brain damage from long term marijuana use is chronicled in this 2 minute video.
“This study shows long-term, heavy cannabis use causes significant brain injury, memory loss, difficulties learning new information, and psychotic symptoms, such as delusions of persecution, paranoia, delusions of mind-reading, and bizarre social behaviors in even non-vulnerable users.”
Data Show Anatomical Brain Abnormalities from Marijuana Use.

In the human brain, the hippocampus is associated with the regulation of emotion and memory, while the amygdala controls fear and aggression. Recently a study was conducted by Dr. Murat Yücel and associates from the ORYGEN Research Centre and the Neuropsychiatry Centre at the University of Melbourne in order to determine whether long-term heavy cannabis use is associated with gross anatomical abnormalities in two cannabinoid receptor–rich regions of the brain, the hippocampus and the amygdala.
In the study, Yucel’s team did high-resolution MRIs on 15 men who smoked more than five joints a day for more than 10 years with no history of poly-drug abuse. They compared those with scans of 16 men who did not use marijuana. In addition, all the men took verbal memory tests and were examined for symptoms of psychiatric disorders.
Results indicated that the hippocampus of marijuana users was 12 percent smaller, and that the amygdala of marijuana users was 7.1 percent smaller than among nonusers. Cannabis use also was associated with sub-threshold symptoms of psychotic disorders. Lead researcher Murat Yücel said, “This study shows long-term, heavy cannabis use causes significant brain injury, memory loss, difficulties learning new information, and psychotic symptoms, such as delusions of persecution, paranoia, delusions of mind-reading, and bizarre social behaviors in even non-vulnerable users.”
“The more marijuana was used, the more these individuals were likely to show reduced brain volumes in the hippocampus and amygdala, as well as being more likely to develop symptoms of psychotic disorders and to have significant memory impairment.” “There is ongoing controversy concerning the long-term effects of cannabis on the brain,” the authors write. “These findings challenge the widespread perception of cannabis as having limited or no neuroanatomical sequelae. Although modest use may not lead to significant neurotoxic effects, these results suggest that heavy daily use might indeed be toxic to human brain tissue.
Further prospective, longitudinal research is required to determine the degree and mechanisms of long-term cannabis-related harm and the time course of neuronal recovery after abstinence.” Author Affiliations: ORYGEN Research Centre (Drs Yücel, Whittle, and Lubman) and Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne and Melbourne Health (Drs Yücel, Whittle, Fornito, and Pantelis), Melbourne, Australia; School of Psychology and Illawarra Institute for Mental Health, University of Wollongong, Wollongong, Australia (Dr Solowij and Ms Respondek); and Schizophrenia Research Institute, Sydney, Australia (Dr Solowij). All text and images from Fair Use.
Regional Brain Abnormalities Associated With Long-term Heavy Cannabis Use. Murat Yücel, PhD, MAPS; Nadia Solowij, PhD; Colleen Respondek, BSc; Sarah Whittle, PhD; Alex Fornito, PhD; Christos Pantelis, MD, MRCPsych, FRANZCP; Dan I. Lubman, MB ChB, PhD, FRANZCP; General Psychiatry. 2008;65(6):694-701.


{ 8 comments… read them below or add one }
Well this is not encouraging, my nephew is smoking marijuana since the age of 14 he is now 23 , he does not seem to be affected by it, no memory loss, difficulties learning new information, paranoia or psychotic symptoms , but does he show reduced brain volumes ?
And is this for ever?
I love and enjoy reading you blog. I will keep visiting you post. Thanks for the information and advises.
Zeriva, you’re mistaken if you think your nephew hasn’t been affected by his long term use of marijuana. Have a full physical and medical evaluation and then I’m sure you’ll reconsider.
does the brain heal from these injuries? like delusions of mind-reading, and bizarre social behaviors in even non-vulnerable users.” please let me know
I find this interesting that an recovery web site shows long term Marijuana use cause brain damage,.Web Md says that Marijuana does not cause any long term brain damage. http://www.webmd.com/mental-health/news/20030701/heavy-marijuana-use-doesnt-damage-brain
Here is a even better one Marijuana may show Cancer curing properties. http://www.webmd.com/lung-cancer/news/20070417/marijuana-may-fight-lung-tumors
Ill take the studies from WebMd over this quakes advice any day.
I find it very interesting that this study conflicts with every other study regarding the effects of marijuana on the brain. I also surprised that any study that uses only 15 people and no control group, and then makes the claim that the differences in the amount that each men used is directly linked to differences of brain structure within this group. How the hell did they measure that. Let me tell you as someone that does research for a living. This study is not science! And it should not be published as science. Every other brain study says that marijuana preserves brain tissue. So I’m convinced that this is probably propaganda.
Hi
I am the Mother of a 21 yr old son He has been smoking pot since 13 yrs old every day I dont know how much. He was Honors student till Gr 11 Then lost ambition to study Has lost most jobs he held
Because I see him all the time, I have not noticed a BIG change I know for sure his memory is SHOT The brilliant kid is now lazy, slleeps all day, no intention oif finding a job, and I cannot support him financially any more He had several severe anxiety attacks
His Dad in Australia said come for a visit AND we hoped he would go study something there
He has been there for 3 days and my ex husband has just informed me that Frank’s mind is gone – he has not seen him for 4 yrs so I guess it was instantly clear to him .
Frank was constantly losing important documents, could not remember to pick up more than 2 articles from a store etc
We are trying to get rehab facility? Any advice on what to look for
DOES one ever get the memory BACK?? Could you please respond to my email???
cmorton@globaltech.bc.ca
THANKS
We think that taking any drug that abuses the body is wrong.
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