An annual government study of marijuana potency found that the average THC content in street samples of the drug topped 10 percent for the first time last year, CNN reported May 14.

The average THC level in marijuana has been rising for years, according to researcher Mahmoud ElSohly of the University of Mississippi's Potency Monitoring Project, who predicts that levels of the drug's main psychoactive ingredient will continue to rise for several more years before leveling off at 15-16 percent. In 1983, the average marijuana sample contained 4 percent THC, according to ElSohly.

Experts say that experienced users may smoke less of the potent pot to get the same high, but that inexperienced users may not know to moderate their use and risk side-effects like dysphoria, paranoia, and irritability.

"The children I'm most worried about are children who are heavy users ...people who use it on a daily basis," said Lawrence Brain, a child psychiatrist in Maryland.

However, Brain said that the findings on marijuana potency were unlikely to change youth behavior. "Telling them it's 10 percent -- three times more potent than what their parents smoked -- is not an argument they are likely to buy into or to even utilize in any constructive sort of way," he said. "I think they do what they do today. I don't think they consider or reflect on what it might have been like 30 years ago."