What came first: the stoner or the law?

 Ever since the state-scale referendums in 2014 began legalizing adult use of marijuana, a
common concern amongst opponents of marijuana legalization is the overall uptick in marijuana use that will stem from said legalization. Although marijuana use has increased since 2015, a new study from the Addiction journal rejects that the increase was caused by the increased legalization of marijuana and marijuana derivatives. Rather, an Addiction study found that a change in public opinion has led to a change in legislation, not the other way around. According to Tom Angell’s Study: Rise in Marijuana Use Not Caused by Legalization: 

Researchers at the Public Health Institute's Alcohol Research Group analyzed data from periodic National Alcohol Surveys and stacked its results on marijuana use against changes in state laws.

Twenty-nine states and Washington, D.C. have comprehensive legal medical cannabis programs, and eight states and D.C. have legalized marijuana for adults over 21 years of age.

They found that instead of being caused by policy changes, the rise in cannabis use was "primarily explained by period 

effects," meaning societal factors that affect populations across age and generational groups. The authors identify a decreasing disapproval of marijuana use as one such factor potentially at play.

But they are clear that the rise in use was not caused by changes to marijuana laws.

"The steep rise in marijuana use in the United States since 2005 occurred across the population and is attributable to general period effects not specifically linked to the liberalization of marijuana policies in some states," the paper's abstract says.

    Angell furthers his "chicken or the egg" argument by pointing to similar factors. For example: due to the growing acceptance of marijuana use by the public at large, coupled with the changes in regulation that reflect this acceptance, Angell believes that more people are simply willing to admit to using marijuana or marijuana derivatives. This logic leads Angell to believe that increased use and acceptance of marijuana has influenced recent legalization, rather than the other way around.