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Cars Crashes And Mmj.

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“Study” on marijuana and driving isn’t really a study, but is loaded with propaganda

by Dr. Joe McSherry

November 17, 2011


Wikipedia defines propaganda as “present[ing] information primarily to influence an audience. Propaganda is often biased, with facts selectively presented (thus possibly lying by omission) to encourage a particular synthesis, or uses loaded messages to produce an emotional rather than rational response to the information presented. The desired result is a change of the attitude toward the subject in the target audience to further a political, or other type of agenda.”


“Marijuana Use and Motor Vehicle Crashes”1 is a typical example of propaganda funded by the National Institute on Drug Abuse (NIDA) and, ultimately, us, the taxpayers. NIDA, which does not consider finding good things about illegal drugs part of its mandate, funds studies to look for harmful effects of illegal drugs, including cannabis. This is not research but statistical manipulation (meta-analysis) of selected prior research articles. The only science involved was described in the original articles.


In this case, Dr. Li’s article starts with the observation that the federal government considers cannabis to have “no currently accepted medical use,” in contrast with “16 states and the District of Columbia [which] have enacted legislation to decriminalize medical marijuana [cannabis].” The authors do acknowledge there are lots of articles on medical use (the U.S. Government, incidentally, owns a patent on medical uses as well as a monopoly on the availability of cannabis for research). The discussion of medical cannabis and legalization do not impact driving but are the target of this article.


Lies by omission: Dr. Li, et al. reference an article by Dr. DP Tashkin on the harmful effects on the respiratory system caused by cannabis use, written in 1987. Follow up research by Tashkin designed to find the harmful effects on the respiratory system, and published in 2007,2 did not find cannabis to be associated with harmful effects. The 2007 article was omitted.


In another example, Dr. Li, et al. reference an article by Dr. K.I. Bolla published in 2002 to document the “host of adverse effects” of long-term cannabis use. This was another NIDA article. With careful reading, including a review of data published separately online, one learns that when subjects were stratified by IQ, the below average persons who used more cannabis performed less well. The above average IQ persons who used more cannabis performed better. One could conclude from the article that chess players who test negative for cannabis use might be advised on the increased accuracy associated with cannabis use. The authors only dwelt on the below average users studied, omitting the Carl Sagans in their study.


Dr. Li, et al. declare “[t]he only study that failed to detect a significant association between marijuana use and crash risk was a small case-control study conducted in Thailand … .” The authors, however, omit the conclusions of one of the articles from which the meta-analysis is constructed. Dr. KL Movig,3 the author of one of the nine source articles, studied the effects on driving of alcohol and other sedatives, amphetamines, opiates, cocaine, and cannabis, as well as combinations of these. What was found was the combination of drugs is the greatest hazard. No rocket science there — if your judgment is trashed by alcohol and you add a sedative or stimulant you are not going to be a safe driver. “[D]rug use, especially alcohol, benzodiazepines and multiple drug use and drug–alcohol combinations, among vehicle drivers increases the risk for a road trauma accident requiring hospitalization … No increased risk for road trauma was found for drivers exposed to cannabis.” Lying through omission.


The other articles combine apples and oranges, and each stands on the quality of research presented. The meta-analysis is a smoothie. Emphasizing the author’s position on this, the discussion ends as the introduction began, confounding medical cannabis use with recreational use and implying states with medical marijuana laws should see an increase in marijuana-related automobile accidents.


NIDA tried to connect smoking hazards of tobacco with smoking cannabis and failed. This article attempts to connect the hazards of drunk driving with drivers who use cannabis at any time, whether for recreational or medical purposes. Taxpayers should insist that the government not only end the war on drugs but also eliminate NIDA. After all, NIDA controls all the cannabis for research, and the DEA prevents approval of any alternative source of cannabis. Yet, NIDA has refused to provide marijuana to FDA-approved studies on the medical benefits of cannabis. Finally, the propaganda produced by NIDA is used by opponents of medical marijuana as a political tool. The ONDCP also substitutes NIDA propaganda for the science on cannabis, so that it can refuse to consider policy changes to allow medical cannabis or legalization, as occurred last week with the response to the “We the People” petition to the White House signed by 50,000 citizens. Eliminating NIDA, the DEA, and the ONDCP will provide savings to the federal budget. And that is a fact.


1 Mu-Chen Li, Joanne E. Brady, Charles J. DiMaggio, Arielle R. Lusardi, Keane Y. Tzong, and Guohua Li. “Marijuana Use and Motor Vehicle Crashes.” Epidemiologic Reviews (2011): mxr017v1-mxr017.


2 Hashibe M, Morgenstern H, Cui Y, Tashkin DP, Zhang ZF, Cozen W, Mack TM, Greenland S. “Marijuana use and the risk of lung and upper aerodigestive tract cancers: results of a population-based case-control study.” Cancer Epidemiol Biomarkers Prev. October 2006, 15(10): 1829-34.


3 K.L.L. Movig, M.P.M. Mathijssen , P.H.A. Nagel , T. van Egmond, J.J. de Gier, H.G.M. Leufkens, A.C.G. Egberts. “Psychoactive substance use and the risk of motor vehicle accidents.” Accident Analysis and Prevention 36 (2004): 631–636. [An excellent source on the risks of driving with alcohol and drugs.]


If you have a science-based question about marijuana, email it to us at state@mpp.org, and it may be answered in our upcoming “Ask Dr. McSherry” feature.



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