Posted by izybx:
Another recent study from our laboratory ... found virtually no significant differences between 108 heavy cannabis users and 72 controls -- screened to exclude those with current psychiatric disorders, medication use, or any history of significant use of other drugs or alcohol -- on a battery of ten neuropsychological tests after 28 days of supervised abstinence from the drug," he said.
Bang, harvard study.
NO BRAIN DAMAGE SEEN IN MARIJUANA-EXPOSED MONKEYS
California NORML Reports, April 1992
Two new scientific studies have failed to find evidence of brain damage in monkeys exposed to marijuana, undercutting claims that marijuana causes brain damage in humans.
The studies were conducted by two independent research groups. The first, conducted by Dr. William Slikker, Jr. and others at the National Center for Toxicological Research in Arkansas examined some 64 rhesus monkeys, half of which were exposed to daily or weekly doses of marijuana smoke for a year. The other, by Gordon T. Pryor and Charles Rebert at SRI International in Menlo Park, California, which is still unpublished, looked at over 30 rhesus monkeys that had inhaled marijuana one to three times a day over periods of 6 to 12 months. Neither study found evidence of structural or neurochemical changes in the brains of the monkeys when examined a few months after cessation of smoking.
The new results cast doubt on earlier studies purporting to show brain damage in animals. The most famous of these was a study by Dr. Robert Heath, who claimed to find brain damage in three monkeys heavily exposed to cannabis. Heath's results failed to win general acceptance in the scientific community because of the small number of subjects, questionable controls, and heavy doses.
Bang another one.
[Edited by - izybx on 12-08-2006 10:19 AM]
Every once in a while, you stick your foot so far down your mouth it rips you a new ass hole. Thats what you just did. Congratulations.
First of all, I went to Harvard medical school, so the irony here is quite entertaining. I don't want to embarass you, but since you were uneducated and rude enough to make the statement you made, I feel obligated to throw some articles your way. Some are from Harvard. Some are from Hopkins for good measure.
To thoroughly convince you of your idiocy, the last two are from your favorite
Harvard researcher, Harrison Pope, who recently has changed his tune quite a bit. Especially look at the last article by Dr. Pope.
For those actually interested in the research, Pope's initial studies were
retrospective reviews using arbitrary neurological tests - both the choice of primary outcomes and confounding variables were highly questionable. The gold standard for clinical research is a prospective interventional study.
Here are a plethora of articles demonstrating long-term effects of marijuana use:
1. Dose-related neurocognitive effects of marijuana use.Bolla KI, Brown K, Eldreth D, Tate K, Cadet JL.
Department of Neurology,
Johns Hopkins University School of Medicine, Hopkins Bayview Research Campus, Baltimore, MD 21224, USA. kbolla@jhmi.edu
CONCLUSIONS: Very heavy use of marijuana is associated with persistent decrements in neurocognitive performance even after 28 days of abstinence.
2. Solowij N, Stephens RS, Roffman RA, Babor T, Kadden R, Miller M, Christiansen K, McRee B, Vendetti J; Marijuana Treatment Project Research Group.
National Drug and Alcohol Research Centre, University of New South Wales, Sydney, NSW 2052, Australia. n.solowij@unsw.edu.au
CONCLUSIONS: These results confirm that long-term heavy cannabis users show impairments in memory and attention that endure beyond the period of intoxication and worsen with increasing years of regular cannabis use.
3. Arch Gen Psychiatry. 1996 Nov;53(11):1051-7. Links
Cognitive correlates of long-term cannabis use in Costa Rican men.Fletcher JM, Page JB, Francis DJ, Copeland K, Naus MJ, Davis CM, Morris R, Krauskopf D, Satz P.
Department of Pediatrics, University of Texas-Houston Medical School, USA.
CONCLUSION: Long-term cannabis use was associated with disruption of short-term memory, working memory, and attentional skills in older long-term cannabis users.
4. Psychopharmacology (Berl). 2006 Apr;185(3):358-68. Epub 2006 Mar 7. Links
Long-term effects of frequent cannabis use on working memory and attention: an fMRI study.Jager G, Kahn RS, Van Den Brink W, Van Ree JM, Ramsey NF.
Rudolf Magnus Institute of Neuroscience, Department of Psychiatry, A.01.126, University Medical Center, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands. gjager@umcutrecht.nl
Conclusions: For working memory, a more specific region-of-interest analysis showed that, in comparison to the controls, cannabis users displayed a significant alteration in brain activity in the left superior parietal cortex.
5. Brain Res Cogn Brain Res. 2005 Apr;23(1):107-18. Links
Neuroimaging of marijuana smokers during inhibitory processing: a pilot investigation.Gruber SA, Yurgelun-Todd DA.
Cognitive Neuroimaging Laboratory, Brain Imaging Center, McLean Hospital, Department of Psychiatry, Harvard Medical School, Belmont, MA 02478, USA. gryber@mclean.harvard.edu
Conclusions: Findings from this study are consistent with the notion that substance abusers demonstrate evidence of altered frontal neural function during the performance of tasks that involve inhibition and performance monitoring, which may affect the ability to make decisions.
6. Exp Clin Psychopharmacol. 2006 Nov;14(4):422-8. Links
Altered regional blood volume in chronic cannabis smokers.Sneider JT,
Pope HG Jr, Silveri MM, Simpson NS, Gruber SA, Yurgelun-Todd DA.
Cognitive Neuroimaging Laboratory, Brain Imaging Center, McLean Hospital, Belmont, MA 02478, USA. jtsneider@mclean.
harvard.edu
Results: Cannabis users demonstrated significantly increased blood volumes in the right frontal area (p < .05), in the left temporal area (p < .005), and in the cerebellum (p < .005) relative to comparison subjects.
7. Drug Alcohol Depend. 2003 Apr 1;69(3):303-10. Links
Early-onset cannabis use and cognitive deficits: what is the nature of the association?
Pope HG Jr, Gruber AJ, Hudson JI, Cohane G, Huestis MA, Yurgelun-Todd D.
Department of Psychiatry,
Harvard Medical School, McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA. pope@mclean.harvard.edu
RESULTS: The 69 early-onset users (who began smoking before age 17) differed significantly from both the 53 late-onset users (who began smoking at age 17 or later) and from the 87 controls on several measures, most notably verbal IQ (VIQ).
CONCLUSIONS: Early-onset cannabis users exhibit poorer cognitive performance than late-onset users or control subjects, especially in VIQ.
Bang, multiple Harvard studies.
Sh-t in the popcorn to go with sh-t on the court. Its a theme show like Medieval times.
12/6/2006 10:14 PM
