cannabisnews.com: Marijuana's Effects Linger in The Brain





Marijuana's Effects Linger in The Brain
Posted by CN Staff on February 07, 2005 at 14:42:27 PT
By Jennifer Warner, WebMD Medical News
Source: WebMD 
The effects of marijuana in the brain may linger long after the last joint goes out. A new study shows that blood flow to the brain in people who smoked marijuana remained altered up to a month after they last smoked pot.Researchers say the findings may help explain the problems with memory and thinking found in previous studies of chronic marijuana users.
Marijuana's Effects on the BrainIn the study, which appears in the Feb. 8 issue of Neurology, researchers studied the blood flow in brain arteries of 54 marijuana users and 18 nonusers.The marijuana users volunteered to participate in an inpatient program and abstained from marijuana use for a month.Blood flow in the brain was analyzed at the beginning of the study and at the end of the month for the marijuana users.Researchers found blood flow was significantly higher in marijuana users than in nonusers, both at the beginning and at the end of the study. However, the marijuana users also had higher scores on the pulsatility index (PI), which is a measure of resistance to blood flow.Researchers say the level of resistance to blood flow among light and moderate marijuana users improved over the course of the abstinence month. But there was no improvement among heavy marijuana users.This resistance is thought to be caused by the narrowing of blood vessels that happens when the body's own ability to regulate the circulatory system becomes impaired."The marijuana users had PI values that were somewhat higher than those of people with chronic high blood pressure and diabetes," says researcher Ronald Herning, PhD, of the National Institute on Drug Abuse in Baltimore, Md., in a news release. "However, their values were lower than those of people with dementia. This suggests that marijuana use leads to abnormalities in the small blood vessels in the brain, because similar PI values have been seen in other diseases that affect the small blood vessels." Light marijuana users smoked two to 15 joints per week, moderate users smoked 17 to 70 joints per week, and heavy users smoked 78 to 350 joints per week.Sources: Herning, R. Neurology, Feb. 8, 2005; vol 64: pp 488-493. News release, American Academy of Neurology.Note: Blood Flow to Brain Altered Weeks After Smoking Pot. Reviewed By Brunilda Nazario, MDSource: WebMD (US Web)Author: Jennifer Warner, WebMD Medical NewsPublished: Monday, February 07, 2005 Copyright: 2005 WebMD Inc.Contact: news webmd.net Website: http://www.webmd.com/CannabisNews Medical Marijuana Archiveshttp://cannabisnews.com/news/list/medical.shtml
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Comment #10 posted by whig on July 31, 2006 at 00:19:39 PT
This study is still being cited
I'm having a conversation with someone on another board, and this gets cited to me by someone who is ostensibly on our side:http://www.firedoglake.com/2006/07/30/late-nite-fdl-a-schadenfreudian-slip/#comment-214921The actual link was a BBC story that we didn't cover here but appears to be the identical study:http://news.bbc.co.uk/1/hi/health/4244489.stmWe really have a problem when our own friends are buying into and disseminating NIDA disinfo.
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Comment #9 posted by JR Bob Dobbs on February 08, 2005 at 02:27:30 PT
Lingering
Alcohol's effects linger in the liver, tobacco's linger in the lungs.But only cannabis smokers linger in jail.
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Comment #8 posted by afterburner on February 08, 2005 at 01:14:02 PT
And Canadian MP Randy White's Minions... 
will be quoting chapter and verse.
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Comment #7 posted by afterburner on February 08, 2005 at 01:10:46 PT
You Can Expect Governor of Alaska to Be Quoting...
this so-called study soon as further evidence of damage done to health in his fossil fuel campaign to re-illegalize cannabis.
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Comment #6 posted by telarus on February 07, 2005 at 19:51:56 PT:
There was Tobacco in them there Joints.
This also hit NewScientist.com, although there was one paragraph that sent me furioulsy hunting through my FireFox History to find it there after I read this article here."To eliminate the effect of tobacco in the joints , Cadet compared his results to those obtained from smokers, who showed normal blood flow. But, says William Notcutt of James Paget Hospital in Norfolk, UK, the longer-term effect on the brain may not have been caused by the same substance that produces the high."The spin on this was brilliant. When I read the article here on CN.com, a little alarm when off in my head, and after scanning through the follow-up articles, and desperatly searching Google and my History today for the inconsistency, I realized that the NewScientist story was the only one to mention that there was TOBACCO IN THE JOINTS. Now, as anyone who has mixed these 2 into a joint knows, the effects are not simply additive but synergetic. Now, you any of you seriously smoke 350-78, or eaven 70-17 joints a week if they were half-and-half????? From the phrasing above, there were were no straight MJ joints used in the study.(xposted to next thread to increase exposure of propoganda spin, heh didn't even see it until 10 minutes of frantic research)
Marijuana makes blood rush to the head
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Comment #5 posted by FoM on February 07, 2005 at 16:24:53 PT
Related Article from Reuters UK
Marijuana Affects Brain Long-Term, Study Finds February 7, 2005 WASHINGTON (Reuters) - Marijuana users have faster blood flow in their brains, even after a month of not smoking, U.S. researchers reported on Monday.The findings suggest they have narrowed arteries, similar to patients with high blood pressure and dementia, and could help explain reports that heavy marijuana users have trouble on memory tests, said the researchers at the National Institute on Drug Abuse in Baltimore.Ronald Herning and Jean Lud Cadet tested 54 marijuana users, who smoked anywhere between two and 350 joints a week, and 18 non-smokers.They used Doppler sonograms to measure blood flow in volunteers' brains at the beginning of the study and a month later, after everyone agreed to abstain from marijuana for the four weeks.The smokers had faster blood flow, both at the start and after a month of abstinence, Herning and Cadet reported in the journal Neurology.The smokers also had a higher pulsatility index score, or PI, which measures the amount of resistance to blood flow. The researchers believe the higher PI is caused by narrower blood vessels."The marijuana users had PI values that were somewhat higher than those of people with chronic high blood pressure and diabetes," Herning said in a statement."However, their values were lower than those of people with dementia. This suggests that marijuana use leads to abnormalities in the small blood vessels in the brain."They found that blood flow improved in people who smoked up to 70 marijuana cigarettes a week -- people they defined as moderate users -- after a month of avoiding cannabis.Heavy users, who smoked up to 350 joints a week, saw no change in blood flow even after a month, the researchers said.Researchers at Toronto's McGill University have reported that chronic consumers of cannabis lose molecules called CB1 receptors in the brain's arteries.This reduces blood flow to the brain, causing attention deficits, memory loss, and impaired learning ability.  
Copyright: Reuters 2005
 
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Comment #4 posted by FoM on February 07, 2005 at 15:28:08 PT
Then Cannabis Helps With PTSD
Cannabis is good medicine!Pot Shots for Israeli Soldiers: http://cannabisnews.com/news/thread19285.shtmlChemical in Pot Puts Haze on Bad Memories: http://cannabisnews.com/news/thread13606.shtmlStudy: Marijuana Eases Traumatic Memories: 
http://cannabisnews.com/news/thread13601.shtmlPot Blocks Painful Memories, Study Says: 
http://cannabisnews.com/news/thread13600.shtml
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Comment #3 posted by dongenero on February 07, 2005 at 15:12:04 PT
hmm
They hypothesized that increased blood flow is caused by vessels constricting while other studies, I believe, proved cannabis to be a vasodilator. Sheeesh. 
One thing I'll say is that this article is short enough for the minute attention span of most antis but is very short on substance as well.I would be very interested in Dr. Russo's take on the details of this study.
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Comment #2 posted by FoM on February 07, 2005 at 15:06:36 PT
lombar
Let's see, 50 joints per day, average 16 hours of wakefulness equals 3 joints per hour for every hour. If someone could do that I'd say he would never get anything done. LOL!
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Comment #1 posted by lombar on February 07, 2005 at 15:01:12 PT
Doctor should be called R. Herring
"Light marijuana users smoked two to 15 joints per week, moderate users smoked 17 to 70 joints per week, and heavy users smoked 78 to 350 joints per week."Does anyone know anybody who smokes 10-50 joints per day?(or believe that anyone who does would abstain for a month?) With that much smoking the increase in PI is probably directly attributable to smoking itself and not cannabis. Let's see, 50 joints per day, average 16 hours of wakefulness equals 3 joints per hour for every hour. Unless that is for medical usage I'd call that an abuse problem.There is no mention of HOW blood flow was measured. There is also no accounting for the other environmental differences(like body weight, social demographic, occupation, pre-existing conditions etc.).
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