How Marijuana-Legalization Laws Impact Use Trends
The recent legalization of medical marijuana in Colorado provides an alternative pain treatment for those with chronic illnesses, such as cancer. Many believe that the use of marijuana should be extended beyond medical applications. While it has been argued that marijuana has certain benefits, research shows that marijuana can have dangerous effects, such as instances of psychosis among those with a history of marijuana use.
One concern about the passage of laws like the one that Colorado has implemented is that it may affect the overall use of marijuana, and particularly the nonmedical use of marijuana. A recent study examined how marijuana use is affected by legalization by comparing marijuana use and dependence in states with and without medical marijuana legislation (Cerda, Wall, Keyes et al., 2012).
To gather information about marijuana use in states with and without medical marijuana legalization laws, the researchers used Wave 2 from the National Epidemiological Survey on Alcohol and Related Conditions (NESARC). NESARC compiled data on marijuana usage through face-to-face interviews conducted between 2004 and 2005, which involved 34,653 individuals.
As a part of the interviews, the research team used the Alcohol Use Disorder and Associated Disabilities Interview Schedule to determine non-medical use of marijuana over the past 12 months, including levels of dependence and abuse.
The researchers used a linear regression model to determine the prevalence of marijuana use and abuse or dependence based on marijuana legalization laws. They adjusted for demographic variables in their analysis. The researchers also utilized a multilevel logistic regression model that predicted individual’s outcomes using both individual and state-level covariates.
The results showed that non-medical marijuana use in the past year was higher for those states that had medical marijuana laws when compared to states that did not have any laws allowing medical marijuana use. In addition, the abuse and dependence rates were higher in those states with medical marijuana laws.
Abuse and dependence among those who had past-year use was not shown to vary significantly between states with and without medical marijuana laws.
Those residents who lived in the states that had medical marijuana laws were 1.92 times likelier to have past-year marijuana use, and were 1.81 times likelier to abuse marijuana or be dependent.
The authors note that the study is not meant to establish causality between medical marijuana laws and marijuana-related behaviors. It is possible that there is a causal relationship, but that cannot be established through the findings of this study and there are other possibilities. In addition, the study did not examine how marijuana use changes in the years after medical marijuana laws are passed in a particular state.
The study finds that states with medical marijuana laws have higher rates of use and abuse or dependence. It is possible that the passage of such laws leads to a general increased acceptability of the use of marijuana for both medical and recreational use. Further study is required to understand the impact of medical marijuana laws on these attitudes.