Human-sized rat cages used to discourage teen pot use

DENVER, Colo. - "Who will be their guinea pigs?"

That's the question a new ad campaign is asking, aimed at discouraging marijuana use by teens.

It's happening in Colorado, one of a few states that in recent months legalized recreational use of the drug by adults 21 or older.

The anti-pot campaign, created by the state, and by the city of Denver, unveiled several nine-foot-tall human-sized rat cages on Monday that bear a simple message: Because so much is still unknown about pot's effects on kids' brains, teens who do smoke it become unwitting research subjects, reports CBS Denver.

The $2 million "Don't Be a Lab Rat" campaign was reportedly funded by legal settlements with pharmaceutical companies. It will also feature TV commercials that suggest marijuana impairs mental function in teens' still-developing brains and could cause long-term mental problems, according to the station.

"While much still needs to be learned about the effect marijuana has on the brain, enough information is available to cause concern in terms of the negative effects marijuana can have on the developing brains of teenagers," Dr. Larry Wolk, the executive director and chief medical officer at the Colorado Department of Public Health and Environment, said in a statement. "The core premise of the 'Don't Be a Lab Rat' campaign acknowledges that more research is necessary."

The campaign set up cages in various locations around the state, and tarps covering them were expected to be removed Monday.

"Kids buy into it. They understand the research and the facts behind it,"Mike Sukle, one of the campaign's creators, said.

Mason Tvert, one of the primary proponents behind marijuana legalization in Colorado, told CBS Denver he believes the campaign was misguided and won't deter teen usage.

"You don't have to say, 'You're going to become a lab rat and it's going to destroy you.' This is the same type of fear-mongering that's failed to prevent teen marijuana use for decades," he said.

Tvert, who is also the communications director for the pro-pot Marijuana Policy Project (MPP), said teens won't respect the campaign: "All you have to do is be honest with young people. Tell them, 'These are the potential harms of this substance.'"

In a blog post published Friday on its website, MPP said teen marijuana consumption is declining since legalization, citing a news release from the Colorado Department of Public Health and Environment.

The state of Colorado, meanwhile, maintains that addiction is more likely if someone starts using marijuana at a younger age. The state cited a study by the National Institute of Drug Abuse: "Its research shows that 9 percent of people who start using marijuana as an adult will become addicted, whereas 17 percent of people who start using marijuana between the ages of 13 and 25 will become addicted."

Recreational marijuana continues to climb in popularity. Retail marijuana hauled in nearly $25 million in sales in June, its best month yet. Recreational marijuana is drawing close to medical pot for total sales, reports the station.

The state has reportedly collected nearly $30 million in tax revenue for both medical and recreational marijuana since January, when Colorado's first recreational stores opened. Personal marijuana use became legal in the state on Dec. 10, 2012.