La scienza contro i valori dei Radicali: la Cannabis crea gravi problemi al cervello, 21 novembre, 2011, http://www.uccronline.it/

Ultimamente la ricerca scientifica si sta particolarmente dedicando agli effetti negativi della Cannabis, per il grandissimo disappunto del Partito Radicale (e dell’Unione degli atei pseudorazionalisti che sostiene ufficialmente i Festival Antiproibizionisti). In Ultimissima 17/10/11 informavamo che la rivista scientifica “Addiction Biology” ha pubblicato uno studio realizzato da Roy Otten del Behavioural Science Institute of Radboud University Nijmegen, con il quale si dimostra come il fumo di cannabis porta ad un aumento del rischio di sviluppare sintomi depressivi.

Ad esso sono seguiti altri due studi molto importanti (e molto scomodi per l’area culturale laicista). Una meta-analisi svolta dai ricercatori della Columbia University ha infatti esaminato il legame tra uso di marijuana da parte dei conducenti e il rischio di un incidente d’auto, scoprendo che essi hanno più di due volte di probabilità di essere coinvolti in incidenti automobilistici. I ricercatori hanno anche trovato prove che il rischio di incidenti aumenta con la concentrazione di composti della marijuana nelle urine e la frequenza dell’uso di marijuana auto-riferito. Secondo i ricercatori, 8 di 9 studi hanno trovato che i guidatori che fanno uso di marijuana hanno significativamente più probabilità di essere coinvolti in incidenti rispetto ai guidatori che non lo fanno. I risultati dello studio, finanziato dal National Institutes of Health, sono pubblicati su Epidemiologic Reviews.

Il secondo studio in merito, uscito dopo pochi giorni, è quello realizzato da un team di neuroscienziati dell’Università di Bristol, pubblicato sul “Journal of Neuroscienc”, secondo cui il consumo di cannabis causa un disaccoppiamento, una disarmonia tra le funzioni di due importanti zone del cervello: l’ippocampo e la corteccia prefrontale. Di conseguenza l’uso di marijuana danneggia la memoria, la capacità decisionale e provoca disturbi neurologici simili a quelli della schizofrenia, come lo stato confusionale.

Nonostante tutto questo, nella pagina ufficiale di Facebook di Marco Pannella e quella del Partito Radicale si può notare come, alla faccia della ricerca scientifica e della salute dei loro adepti, essi aderiscano apertamente alle pagine sulla legalizzazione della Marijuana.

Linda Gridelli

Marijuana Use May Double the Risk of Accidents for Drivers, Study Finds

Web address:  http://www.sciencedaily.com/releases/2011/10/111006173453.htm

ScienceDaily (Oct. 6, 2011) — Over 10 million people age 12 or older are estimated to have driven under the influence of illicit drugs in the prior year, according to a 2009 National Survey on Drug Use and Health. While marijuana is the most commonly detected non-alcohol drug in drivers, its role in causing crashes has remained in question.

To examine the link between marijuana use by drivers and risk of a car accident, researchers at Columbia University did a meta-analysis of nine epidemiologic studies and found that drivers who test positive for marijuana or report driving within three hours of marijuana use are more than twice as likely as other drivers to be involved in motor vehicle crashes. The researchers also found evidence that crash risk increases with the concentration of marijuana-produced compounds in the urine and the frequency of self-reported marijuana use.

According to the investigators 8 of 9 studies found that drivers who use marijuana are significantly more likely to be involved in crashes than drivers who do not. Only one small case-control study conducted in Thailand, where the prevalence of marijuana use is far lower than reported elsewhere, was the exception.

Full study findings are published online in Epidemiologic Reviews.

The analysis indicates that 28% of fatally injured drivers and more than 11% of the general driver population tested positive for non-alcohol drugs, with marijuana being the most commonly detected substance.

Guohua Li, MD, DrPh, professor of Epidemiology at Columbia University's Mailman School of Public Health, and senior author points out that although this analysis provides compelling evidence for an association between marijuana use and crash risk, one should be cautious in inferring causality from these epidemiologic data alone. However, "if the crash risk associated with marijuana is confirmed by further research, this is likely to have major implications for driving safety and public policy. It also would play a critical role in informing policy on the use of medical marijuana."

"Given the ongoing epidemic of drug-impaired driving and the increased permissibility and accessibility of marijuana for medical use in the U.S., it is urgent that we better understand the role of marijuana in causing car accidents."

Study co-authors from the Department of Epidemiology are Dr. Charles DiMaggio, associate professor; Joanne Brady, PhD candidate; and Keane Tzong, MPH candidate.

The research was supported by the National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health.

Story Source:

The above story is reprinted from materials provided by Columbia University's Mailman School of Public Health, via EurekAlert!, a service of AAAS.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

M.-C. Li, J. E. Brady, C. J. DiMaggio, A. R. Lusardi, K. Y. Tzong, G. Li. Marijuana Use and Motor Vehicle Crashes. Epidemiologic Reviews, 2011; DOI: 10.1093/epirev/mxr017

How Cannabis Causes 'Cognitive Chaos' in the Brain

Web address: http://www.sciencedaily.com/releases/2011/10/111025172633.htm

ScienceDaily (Oct. 25, 2011) — Cannabis use is associated with disturbances in concentration and memory. New research by neuroscientists at the University of Bristol, published in the Journal of Neuroscience, has found that brain activity becomes uncoordinated and inaccurate during these altered states of mind, leading to neurophysiological and behavioural impairments reminiscent of those seen in schizophrenia.

The collaborative study, led by Dr Matt Jones from the University's School of Physiology and Pharmacology, tested whether the detrimental effects of cannabis on memory and cognition could be the result of 'disorchestrated' brain networks.

Brain activity can be compared to performance of a philharmonic orchestra in which string, brass, woodwind and percussion sections are coupled together in rhythms dictated by the conductor. Similarly, specific structures in the brain tune in to one another at defined frequencies: their rhythmic activity gives rise to brain waves, and the tuning of these brain waves normally allows processing of information used to guide our behaviour.

Using state-of-the-art technology, the researchers measured electrical activity from hundreds of neurons in rats that were given a drug that mimics the psychoactive ingredient of marijuana. While the effects of the drug on individual brain regions were subtle, the drug completely disrupted co-ordinated brain waves across the hippocampus and prefrontal cortex, as though two sections of the orchestra were playing out of synch. Both these brain structures are essential for memory and decision-making and heavily implicated in the pathology of schizophrenia.

The results from the study show that as a consequence of this decoupling of hippocampus and prefrontal cortex, the rats became unable to make accurate decisions when navigating around a maze.

Dr Jones, lead author and MRC Senior Non-clinical Fellow at the University, said: "Marijuana abuse is common among sufferers of schizophrenia and recent studies have shown that the psychoactive ingredient of marijuana can induce some symptoms of schizophrenia in healthy volunteers. These findings are therefore important for our understanding of psychiatric diseases, which may arise as a consequence of 'disorchestrated brains' and could be treated by re-tuning brain activity."

Michal Kucewicz, first author on the study, added: "These results are an important step forward in our understanding of how rhythmic activity in the brain underlies thought processes in health and disease."

The research is part of a Medical Research Council (MRC)-supported collaboration between the University and the Eli Lilly & Co. Centre for Cognitive Neuroscience that aims to develop new tools and targets for treatment of brain diseases like schizophrenia and Alzheimer's disease.

Story Source:

The above story is reprinted from materials provided by University of Bristol.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

M. T. Kucewicz, M. D. Tricklebank, R. Bogacz, M. W. Jones. Dysfunctional Prefrontal Cortical Network Activity and Interactions following Cannabinoid Receptor Activation. Journal of Neuroscience, 2011; 31 (43): 15560 DOI: 10.1523/JNEUROSCI.2970-11.2011