DENVER -- Colorado is getting a boost to help fight drug addiction in the state.

The U.S. drug czar came to Denver Wednesday to announce a $15 million grant from the federal government over the next five years. The money is to help prevent drug addiction and Colorado is one of four states to get it.

During his announcement at South High School, John Walters talked specifically to students, telling them to remind others to be drug-free.

"Substance abuse is not a lifestyle choice. It's a disease," Walters said. "Marijuana has created a blind spot in our society. It's not taken seriously, yet it is the most serious cause of treatment needed among illegal drugs."

He said it's so serious that nearly one in 10 Colorado children admit to trying marijuana once by the age of 13. And he said many of them get the marijuana for free.

"I was a freshman in drama class when two guys came up and said, 'You want to ditch class and come to the park and smoke?' I was like, 'No,'" said South High senior Steven Moreno.

The grant will help boost screening and drug prevention programs and will go to clinics and emergency rooms in southeastern Colorado and Denver.

The idea is to identify and help certain substance abusers before they become addicted.

"The substance rewires the brain. In order to feel well, you need the substance. It sneaks up like a thief in the night," Walters said.

While some students question whether this initiative will work, supporters say something needs to be done.

"Most of the people I know who smoke marijuana do it because it's a rebellious thing. So more prevention means more rebelling and more doing it," said South High junior Emily Anderson.

"The progress has been made and it's important but we need to go further, clearly," Walters said.

Overall, drug use among teens dropped 19 percent in 2005. That's 700,000 fewer drug users than in 2001.

Walters said Florida, Massachusetts and Wisconsin will all receive similar funding from the U.S. Health and Human Services Department.

On the same that day Walters came to town, a controversial billboard featuring him was put up in south Denver.

The billboard was bought by SAFER, a group that supports Amendment 44, which would give adults over 21 the right to have less than an ounce of marijuana on them.

SAFER said alcohol is a more dangerous substance than marijuana and the group believes the government should promote that.

"They're running an anti-marijuana campaign and they're very open about that. We think it's about time they start worrying about drugs that kill people and not about drugs that have never killed someone in history," said Mason Tvert, SAFER's campaign director.

Similar billboards will be going up in Grand Junction and Colorado Springs in the coming weeks.