A meta-analysis of medical studies around the developed world in the field has persuaded a University of Haifa public health expert that legalization of medical cannabis does not lead to an upswing in recreational use of marijuana – illegal in Israel.The use of marijuana for reducing severe pain and other medical uses – which 22,000 Israeli patients are authorized to do – does not pose a threat to the health or security of the public, Dr. Sharon Sznitman, a senior lecturer in the School of Public Health’s department of health promotion, said on Tuesday.She noted, however, that legalization of the drug is “accompanied by commercialization has been shown to increase use” of cannabis.Her article on the subject has just appeared in the International Journal of Drug Policy.Marijuana is the most commonly used among forbidden drugs. Israel is among the leaders in the growing number of states that allow its use for serious medical conditions, said Sznitman. “At the same time, there is growing concern that legalization of medical cannabis can harm public health and safety and lead to harm, such as more recreational use and higher crime rates,” she suggested.Sznitman and her doctoral student, Yuval Zolotov, found 5,567 articles in the medical literature on medical cannabis.Only 24 were peer-reviewed and found suitable to the question at hand. In a broad analysis of the articles and comparing their research methodology, “one can get an in-depth and exact picture of the reality about the effects of legalization of medical cannabis,” said Zolotov. Commonly held views on the influence of medical cannabis legalization “lack a basis in research,” the two researchers wrote. For example, they said many studies that looked into whether the use of marijuana for medical uses increases recreational use did not find any evidence of that. But when legalization was accompanied by commercialization – such as advertising and production of other products with marijuana such as cookies and candies – it was possible to find evidence that illegal use increased.The Haifa researchers also found no basis for the claim that legalization of medical cannabis spurs a rise in crime.As for fears that allowing the use of medical cannabis will strengthen the black market for marijuana, the findings were not clear cut, and more research has to be done, they wrote.“The world trend is of legalizing medical cannabis, and it requires the attention of researchers to reach strong conclusions on the effects on public health and safety. We know from past studies on cigarettes and alcohol that commercialization – and not legalization – leads to increased use. In Israel, there is no real commercialization of marijuana, and on the basis of existing studies one can say today that allowing the use of medical cannabis will not pose a threat to our public health and safety,” they concluded.