increases its rewarding effects and likelihood of transitioning into addiction. >> how much stronger is it? >> you see the barbed wire, obviously, on the fences. >> well, i traveled to mississippi where marijuana is illegal, but here on the campus of one of the country's oldest universities, ole miss, a huge stash of marijuana is under lock and key. >> this is our vault. >> this is some pretty tight security. look at this door. >> mahmoud runs what's called a marijuana potency project. what's the potency of this? >> this is about 8%. >> for three decades now his team has analyzed weed confiscated from drug busts. >> this is 36% thc. you can smell it. it has a good aromatic smell. >> how much is this worry you, 36% thc confiscated? >> very dangerous material. for someone that is not experienced in marijuana smoking