Across the country, efforts to make marijuana more accessible have quickly gained traction. Medical marijuana is now legal in 23 states, and recreational use is also legal in four states and the District of Columbia.

Science, however, hasn't quite caught up. Largely due to its illegal status, there's been very little research done on marijuana's health effects. And researchers don't fully understand how pot affects the developing teenage brain.

This may explain the why the nation's pediatricians have changed their recommendations on marijuana and children.

On Monday, the American Academy of Pediatrics revised its policy on medical marijuana, saying pediatricians should avoid prescribing it to children until more research is done, except in cases where patients are suffering from chronic, debilitating conditions. The pediatrics group is also recommending the decriminalization of weed, but it's advising against legalization.

Well, that's confusing. So we called up Dr. Seth Ammerman, a pediatrician at Stanford University who wrote the policy paper. Arresting teens who use pot won't do them any good, Ammerman says. Hundreds of thousands of adolescents and teens have been incarcerated for marijuana possession, "and the vast majority of marijuana-related arrests are minority youths."

The pediatricians' stance is that marijuana use among young people is a public health issue rather than a criminal justice issue, and it should be treated as such.

Its views on legalizing pot for recreational use, however, are more conservative.

"There's no evidence that legalizing will benefit youth," Ammerman tells Shots. "And the concern is that legalization will increase youth access to marijuana and maybe increase use."

Marijuana hasn't been legal anywhere in the U.S. for very long, so no one knows how these changing laws will affect teen usage rates. But if marijuana companies start marketing their products like alcohol and tobacco companies have done, kids and teens could be affected, Ammerman says.

"We would certainly be willing to revisit the issue as new data comes up," he adds. "But for now, let's not get into the position where we're looking back a decade from now and saying, 'Oh God, we've now addicted a bunch more kids.' "

Convincing kids that they should stay away from weed can get tricky, the pediatricians acknowledge, especially as support for legalization grows. Part of the issue is that campaigns to legalize marijuana often portray it as a benign substance, says Dr. Leslie Walker, chief of the adolescent medicine division at Seattle Children's Hospital.

"People make arguments that say, 'Oh, this is safer than alcohol, it's safer than tobacco, it's safer than heroin,' " Walker says. And all that may be true, she says. "But marijuana on its own is harmful for adolescents."

Preliminary research suggests that marijuana isn't good for teens' developing brains. And studies show that adolescents who use pot are more likely than adults to become addicted.

Of course, there is still a lot we don't know about marijuana, whether it's used recreationally or medicinally. The AAP policy paper recommends that the Drug Enforcement Agency remove marijuana from the Schedule 1 listing for controlled substances, so that it's easier for researchers to get hold of the substance and study it.

"In the meantime, there's definitely a risk of having a kind of mixed message for teens," says Brendan Saloner, an assistant professor at the Johns Hopkins Bloomberg School of Public Health. "The frank answer is we don't know the best ways to communicate with teens about marijuana."

Refer-madness style scare tactics probably won't work, Saloner says. But both Walker and Ammerman recommend that parents be firm with kids. They should feel empowered to tell kids that using pot when you're under 21 isn't OK, even if they themselves use it. The AAP also recommends that parents set a good example by not smoking around kids.

In Colorado, where adult use is legal, Children's Hospital Colorado suggests that parents "present the facts to your child objectively and use them to explain why marijuana use is still illegal for people under age 21."

In states where marijuana is legal, there are ways to mitigate teen usage, Saloner says.

States can and should control the extent to which companies can advertise marijuana products, he says. "The biggest concern here is edibles — candies and cookies can look really appealing to kids and adolescents," he notes.

Research also shows that the price of alcohol and tobacco can deter adolescents from using it.

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