his November, a record number of states will vote on marijuana use. Five — Arizona, California, Maine, Massachusetts, and Nevada — will consider recreational legalization, and four more — Arkansas, Florida, Montana, North Dakota — will decide on legalizing it for medical purposes. (Though Montana initially approved medical marijuana in 2004, the law has since been drastically curtailed.)
In many ways, the states that currently have legalized marijuana in some form — five including Washington, D.C., with recreational; another 20 with medical — represent ongoing experiments in public health. Those states have provided some interesting lessons thus far, but many questions remain.
Proponents of legalization say that it creates millions in tax revenue, unburdens the criminal justice system, and provides health care options for sick patients. While many public health experts agree about the benefits, they also have concerns about widespread legalization because of the potential consequences of big companies latching on to the marijuana market, the changing public perception of marijuana’s safety, and the increasing potency of marijuana products in legalized states.
Despite that, there’s growing public support for such laws nationwide. A 2015 Gallup poll found 58 percent of Americans support the legal use of marijuana, the third year that supporters have been in the majority.
Recreational marijuana laws allow residents to purchase the drug in a regulatory framework similar to that used for alcohol, including age restrictions and retail licenses. In Colorado, for instance, adults 21 and older can buy up to 1 ounce at a time, though they cannot consume it in public.
The recreational use of marijuana remains illegal on the federal level. But if more states legalize, it will make it harder to enforce that ban, experts say. For instance, if California, with its 40 million residents, passes Proposition 64, it could have national implications.
As one of the first states to legalize recreational marijuana, Colorado has been looked to as a bellwether on the issue. Dr. Larry Wolk, the chief medical officer and executive director of the Colorado Department of Public Health and Environment, said his state’s experience hasn’t raised any alarms thus far. “We don’t see, at least in the short term, any dramatic negative impact to legalization,” he said. “There hasn’t been any public health crisis or safety issue.”
The state has seen some risks, including a rising rate of accidental ingestion of edibles by children and an increase in ER visits by marijuana users. But Wolk is hopeful that they and future legalized states can alter packaging and labels to address those issues.
Wolk said that, so far, their data in Colorado shows that young people have not increased their marijuana use just because it’s legal, a concern among many who are opposed to legalization. Some smaller studies confirm this finding, but nationally, findings are inconsistent state to state. In Nevada and Massachusetts, opponents of legalization are seizing on that concern. Protecting Nevada’s Children is an opposition group against recreational legalization in Nevada, where medical marijuana is already legal. In Massachusetts, a television ad opposing legalization features a mother and daughter wandering through neighborhoods overrun with marijuana stores.
On the other hand, one impact of legalization that has decidedly been observed is an increase in the drug’s potency in legalized areas, said Wayne Hall, director of the Center for Youth Substance Abuse Research at the University of Queensland, who recently studied the effects of cannabis laws in the US. This could account for more ER visits in those states.
Each state’s ballot is significant: If Nevada legalizes recreational marijuana, it will enhance its already booming tourism in Las Vegas. Recreational marijuana in Maine would bring legalized marijuana to the East Coast. But California’s approval could put the most pressure on the DEA to rethink federal prohibition of the drug.
And a changed federal landscape could in turn change the economics of the industry drastically. Stanton Glantz, a professor of medicine at the Center for Tobacco Control Research and Education at the University of California, San Francisco, said he thinks the biggest public health concern of marijuana legalization is what will happen when large corporations start to produce and mass-market marijuana in the same ways they do alcohol or junk food. “The initiatives are written to maximize business potential and minimize regulation,” Glantz said.
He thinks state residents should encourage lawmakers to implement graphic warning labels, bans on flavored products, and barriers to vertical integration — that is, ensuring one company can’t be in charge of the growing, development, and sales of the drug. California’s proposition, for example, would prevent licenses for large-scale marijuana businesses for five years in order to prevent “unlawful monopoly power.”
Medical marijuana, meanwhile, has been legalized by half of states in recent years and enjoys strong public support.
That trend has had a number of effects. For instance, studies have found that after medical marijuana is legalized in a state, its deaths by opioid overdose tend to fall, presumably because people who would have used the latter instead use the former.
It also hasn’t resulted in more adolescents getting their hands on the drug in those states, research shows.
But the widening scope of medical marijuana legalization may have contributed to an aura of healthfulness around the drug, some academics say.
“There’s research that shows that people think marijuana is not only safe but also good for you,” said Glantz. “That is a little bit complicated because there are some therapeutic use of cannabis.” But there’s also some growing evidence that marijuana can be harmful, he said, leading to cognitive impairment, chronic bronchitis, and other potential issues.
Some opponents of North Dakota’s medical marijuana bill, including the North Dakota Medical Association, are concerned that the drug hasn’t been tested by the Food and Drug Administration to determine appropriate dosages.
Research into medical marijuana’s harms and benefits has been hampered by its federal status as a Schedule 1 drug. In 2011, the then-governors of Washington and Rhode Island requested to have marijuana and its “related items” moved to a Schedule 2 drug, but in August of this year, federal drug enforcement authorities announced that marijuana would remain Schedule 1.
As a Schedule 1, marijuana is difficult to research. Scientists have to get Drug Enforcement Administration approval and often increase the security protocols in their labs. As a result, much remains unknown about marijuana’s efficacy and safety for pain management and other therapeutic uses.
This November, how states vote could make a prediction on the national direction for marijuana legalization, recreational or medical. If many of the states vote yes, it could begin a new era in the ongoing experiment of legalized marijuana and public health impacts.