Recent studies show that marijuana may cause psychosis, increase the risk of heart disease, and provoke heart attack. Researchers now tell us that marijuana may be toxic to the brain, especially the left hippocampus. The hippocampus is responsible for short-term memory, spatial navigation, and the left hippocampus plays a large role in language dominance. The study is published online in the June issue of Archives of General Psychiatry, led by Murat Yücel, PhD
Changes in the brain were seen by way of MRI in fifteen heavy marijuana users. All were found to have reductions in hippocampal volume. The participants were male, smoked for more than 10 years without using other drugs, and reportedly smoked more than five joints daily. The study is reportedly the first to measure the long-term effects of marijuana on humans. It’s not completely understood whether the change in brain volume comes from loss of neurons, which make up half of the central nervous system, or glial cells, which comprise the other half. Other possibilities include smaller cells, or alternatively, decreased synapse density - tiny cells that transmit information across neurons. Additionally, "the left hippocampus may be particularly vulnerable to the effects of cannabis exposure and may be more closely related to the emergence of psychotic symptoms”.
Another finding included a 7.1% reduction of the smoker’s amygdala, the portion of the brain that lies close to the hippocampus and affects emotions, arousal, hormonal secretions and fear response.
Further research is planned to measure “the degree and mechanisms of long term cannabis-related harm and the time course of neuronal recovery after abstinence."
Abstract ◦
This story is a joke. Where are all the dead bodies, sick and mentally ill psychotic people? Marijuana has never killed anyone but because crooks get rich on it being illegal we devastate society with prohibition. I find it hard to believe they found 15 people that smoked at least 5 joints a day (that's a lot of pot) and never used any other drug for 10 years. PROHIBITION never works it just causes crime & violence. We build 900 new prison beds and hire 150 more correction officers every two weeks. We arrest someone on a drug charge every 17 seconds. We jail more people than any nation. We spend $69 billion a year on the drug war. In 1914 when ALL drugs were legal 1.3% of our population was addicted to drugs, today 1.3% of our population is STILL addicted to drugs. Over 100,000 people have been killed because of the drug war. The only way to control drugs is to regulate them and end the profits available to criminals just like ending alcohol prohibition did. There’s only been one drug success story in history, tobacco, the most deadly and one of the most addictive drugs. Almost half the users quit because of REGULATION, ACCURATE INFORMATION AND MEDICAL TREATMENT. No one went to jail and no one got killed. JOIN EMAIL LIST, WATCH VIDEOS:
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Hi,
ReplyDeleteI too found the group a bit curious, and yes, that's not a representation of recreational or even medical use of marijuana - it'a a LOT! I also agree that other lifestyle factors could be questioned.
Note, as with all studies, the words used in all of the conclusions, are "may", and "might".
The study is here, for what it's worth. Most medical research is not conclusive until study after study has been performed.
Thank you for your comments.
I blogged about this study as well here http://420-now.blogspot.com/2008/06/australian-study-indicates-link-between.html
ReplyDeleteHowever you should note that the study does not show a change in the brain at all, it doesn't show a reduction in the hippocamapl volume, but rather that the hippocampus in heavy users was smaller. No causality was found, so there is zero evidence that marijuana causes any change in the brain. Any claim as to the cause is pure speculation, the researchers themselves admit they have not causation link. It could be that people with smailler hippocamus and amygdala are prone to heavy marijuana use.
Hi guy,
ReplyDeleteThanks for your comment.
Yes, this is only an observational study. "Changes" would probably be better defined as a variation from the norm. You are correct, the reasons for the smaller hippocampal volume isn't known.
I'm a bit confused though, because the study reads: "Cannabis users had bilaterally reduced hippocampal and amygdala volumes (P = .001), with a relatively (and significantly [P = .02]) greater magnitude of reduction in the former".
My ex husband smoked three to five times a day for years beginning at age fourteen. About eight years ago he attempted to quit and succeeded for a few months before succumbing once again. I don't know if psychosis was in his genetic makeup but at age 45 he has memory problems, emotional problems and decision difficulties.
ReplyDeleteWhile I'm sure it isn't just the marijuana, being the observationist for 24 years, I'm a firm believer in it's contribution to long term negative effects.
For our four children, who are older now, Dad has become our live "this is your brain on drugs" commercial.
Hi,
ReplyDeleteThank you for your comment. The controversy regarding marijuana will continue until definitive studies are performed.
Regardless, of studies, first hand observations are always valuable to others. Thank you for taking your time to give some input.
Most studies today do say that marijuana has a detrimental effect on developing nervous systems.
ReplyDeleteNewer research seems to support that its use is benign after adulthood. However it hampers developing skills to deal with social situations and learning how to deal with uncomfortable emotions, and kills motivation when in use as I have experienced.
Starting at 14 should defiantly have repercussions in the future. He probably hasn't mentally developed much beyond 14. I have some friends that started when they were 12 and it is obvious.
This study is FLAWED a 15 person sample is very narrow and doesn't take into consideration when the users began smoking or use of any other substances.