Ill Effects of Marijuana - NYTimes.com By focusing on changes in California marijuana use since 1996, and then citing a controversial study called into question by some leading think tanks and experts in marijuana policy, "Few Problems With Cannabis for California" (front page, Oct. 27) does not reflect the growing reality of marijuana as a public health and safety threat in that state. First, the important year to look at in California isn't when the medical marijuana initiative passed - 1996 - but rather when it was implemented in the form of "dispensaries," around 2004. And since then there has been a rise in marijuana use and marketing. Second, the single academic study used to substantiate the article's thesis can be called into question for many reasons, including its silence about research that does not conform to the authors" pro-legalization perspective. That research finds that legally protecting dispensaries equals more marijuana use and more problems. Finally, absent from the article was any perspective from educators, prevention groups or treatment centers in California, who have reported that as marijuana has become more normalized and accepted, their work has become harder and, in the case of treatment centers, much more in demand. Also, there was little about the mental or physical health effects of marijuana. Those are not outcomes of marijuana use that should be brushed off, even if bringing them to light hurts the prospects for full legalization in 2016. The writers are, respectively, a former member of Congress and a former senior drug policy adviser in the Obama administration. They are co-founders of Project SAM (Smart Approaches to Marijuana).