Colorado became the first state in the United States to allow the sale of cannabis for recreational use on 1 January 2014. Colorado residents aged 21 years or older may now purchase up to one ounce of cannabis from designated stores around the state (non-residents may purchase up to a quarter of an ounce). Washington State, which also passed a voter initiative to legalize cannabis, will open retail outlets later in 2014.  There are few precedents for legalization of cannabis on this scale. Cannabis is only decriminalized in the Netherlands and Portugal, for instance, while Uruguay’s legalization policy will become effective on 1 April 2014. What might be some of the implications of legalizing cannabis for recreational use in Colorado, and will other states pursue a policy of legalization similar to Colorado? Here are some policy arenas that other states may examine as they consider legalization of cannabis for recreational use.

Increased tax revenue. Retail cannabis will be taxed at a 25% rate in Colorado, which may net $60 million or more in tax revenue in 2014. In addition, drug tourism, like in Amsterdam, is likely to increase, which will result in tourists from around the globe filling up hotels, restaurants, etc.

Decreased criminal justice costs. While people under 21 can still face arrest or fines for possession of cannabis in Colorado, costs associated with policing, prosecuting, and incarcerating people for possession are likely to decline significantly.

Reducing disparities in arrest. At the citizen level, legalization of cannabis could have major implications on arrest records.  A recent report by the American Civil Liberties Union revealed that while black Americans and white Americans use cannabis recreationally at approximately the same rate, black Americans are nearly four times more likely than white Americans to be arrested for cannabis.  Regardless of race, having a criminal record for a cannabis arrest can have a lifelong impact on job and educational opportunities.

Increases in problems associated with cannabis. Problems could include dependence and/or progression from cannabis to other drugs as well as driving under the influence of cannabis. However, this assumes that legalization will attract new cannabis users and/or the frequency of cannabis use among current recreational users will increase.  Additionally, cannabis concentrates, such as “dabs” and “waxes,” which may have two to three times the tetrahydrocannabinol (THC) concentrations, may proliferate on the legal market and result in new forms of misuse.

Safety of cannabis products sold. While cannabis is often perceived as a natural or organic product, it may contain contaminants, such as mold or industrial fertilizers, based on how it is grown or stored. Laboratories have emerged that test cannabis for potency, e.g. levels of THC, as well as contaminants. States that are receiving tax revenue on the sale of cannabis products should take steps to assure buyers that cannabis products sold do not contain harmful contaminants.

Sales and distribution of cannabis across state lines. As production of cannabis increases to meet demand within the state, growers could export and sell excess product to other states. While this is likely to be already happening in states such as Colorado, legalization could increase the scale of selling across state lines.

Federal government’s stance towards legalization. The US Justice Department indicated that they will not interfere with newly enacted cannabis legalization in Colorado or pre-empt legalization efforts in Washington State as long as citizens comply with laws in those states. Under federal law, cannabis remains a schedule I drug, a status indicating that the drug has high potential for abuse and no accepted medical use.

Currently, ballot measures for legalization of cannabis for recreational use are being developed in Alaska, Arizona, and California. Notably, these three states, as well as Colorado and Washington State, had previously legalized cannabis for medical use. These examples suggest that legalization for recreational use is likely to occur in states that have previously legalized cannabis for medical use. Currently, 20 states plus the District of Columbia have legalized cannabis for medical use.

Conflicts statement: I declare that I have the read and understood the BMJ Group policy on declaration of interests and I have no relevant interests to declare.

Stephen E. Lankenau is an associate professor at the school of public health at Drexel University. He is a sociologist who combines public health concerns and mixed method approaches to the study of young adults, drug use, overdose, and infectious diseases. He is the principal investigator of a five year study funded by the National Institute on Drug Abuse examining the impact of medical marijuana use on health and patterns of drug use among young adults in Los Angeles.