Minnesota has become the 22nd state to loosen restrictions on use of marijuana, with its legislature approving the sale and use of medical marijuana on May 15. Other states, including Florida, are considering similar measures.
These changes are happening fast, and we were wondering how people feel about this seemingly inexorable push to decriminalize pot, so we asked, in the latest NPR-Truven Health Analytics Health Poll.
Most people said that allowing use of marijuana for medical purposes is a good idea, with 78 percent saying they're in favor of that. But they were much less positive about legalizing recreational marijuana, as the states of Colorado and Washington have done. Less than half of respondents, 43 percent, backed legalization.
The greater support for medical marijuana may reflect the emotional appeals of patients as detailed in this NPR report on a successful effort to put medical marijuana on the fall ballot.
One of those stories involves Charlotte Figi, a Colorado girl whose parents lobbied the Florida legislature in January, saying that a marijuana extract reduced the girl's seizures from 1,200 a month to one or two.
But there are no randomized controlled trials testing the safety and effectiveness of the special form of marijuana being used to treat Charlotte Figi and other children, and very few on any use of medical marijuana.
For instance, Maine and several other states have approved medical marijuana for treating post-traumatic stress disorder. But the only studies showing that THC, the active ingredient in pot, reduces anxiety have been done in mice.
"There are many more unknowns than knowns," Dr. Orrin Devinsky, a neurologist and head of New York University's Comprehensive Epilepsy Center, told NPR. "And I think the focus of the community — lay and scientific and governmental — should be on getting good information. That should be the real focus of what we need right now."
Some of the new state laws are trying to beef up the skimpy data. Minnesota's law calls for a patient registry and an observational study of cannabis as treatment for a limited list of qualified conditions, including cancer, glaucoma, HIV/AIDS, Tourette Syndrome, Crohn's Disease, ALS and seizures.
In our survey, 90 percent of respondents said that medical professionals should provide education to patients before they buy marijuana for medical use. But given the lack of evidence, it's hard to know what the doctors will be able to tell them.
There's also been very little research on the long-term health effects of recreational marijuana use, including effects on thinking, the lungs and mental health.
That may be why the vast majority of the people we polled, 91 percent, said that states should put age restrictions on access to marijuana. And half of our respondents also think that there also should be age restrictions on use of medical marijuana.
"It's interesting, isn't it? There's this implicit agreement – better be careful with kids," says Dr. Sharon Levy, director of the adolescent substance abuse program at Boston Children's Hospital, and chair of the committee on substance abuse for the American Academy of Pediatrics.
"The reason that people are concerned is that they recognize that this is an addictive substance, and some portion of the population that uses it will become addicted to it and have very bad outcomes," Levy says. "As with all addictive products, the risk is greatest in adolescence."
Given our country's experience with alcohol and tobacco, she fears that making marijuana more available to adults will inevitably lead to more use by adolescents. "I understand that people are saying that adults should be able to use these products, but it's not a fair playing field once you have a big and powerful industry that can manipulate the product, make health claims, and market to kids even though they're saying they're not."
Still, people didn't have strong feelings about any one risk posed by the potential for increased use of marijuana. One-fifth of our respondents said that impairment of the senses was their most significant concern.
Addiction and the possibility that marijuana could be a gateway to harder drugs were cited by 16 percent and 12 percent. But 15 percent said they had no concerns.
"From a medical perspective, for recreational use we really don't know the long term side effects," says Dr. Mike Taylor, chief medical officer for Truven Health Analytics. "Speaking not as a physician but as a father with three kids in their 20s, I think there's a lot of casual marijuana use without any concern as to whether it's safe or not."
The poll results represent responses from 3,010 people; they were interviewed from March 4 through 17, 2014. The margin of error is plus or minus 1.8 percent. You can find the complete list of questions and responses here.