Marijuana use among US high school students is likely to increase as the drug increasingly becomes more legally available, according to a new report in the International Journal of Drug Policy.

The study also intimates that many Americans who currently do not use marijuana do so because it is illegal, and not because they consider anything to be "wrong" with it.

Colorado and Washington states both recently legalized the sale and possession of marijuana for recreational use, and other states around the country are expected to follow suit. Medical marijuana is already available in 19 states and the District of Colombia, and marijuana use has been decriminalized in 15 states.

The new study, which was conducted by researchers affiliated with New York University's Center for Drug Use and HIV Research (CDUHR), found that there is a large proportion of high school students who, for example, do not smoke cigarettes, are religious or who have a peer group that disapproves of drug use, that say they would use marijuana if it were legal.

"Our study focused on intention to use and it was the first to find that groups generally not 'at risk' become more 'at risk' when legalized," said Joseph Palamar, am assistant professor at the NYU Langone Medical Center's Department of Population Health.

Palamar and his colleagues used data from the Monitoring the Future (MTF) study, an ongoing, nationwide survey of the behaviors, attitudes, and values of American secondary school students.

The MTF data revealed that 10 percent of high school students who currently do not use marijuana would try it if it were legal.

The data used in the research was collected prior to Washington and Colorado's legalization of marijuana, but after legalization of medical marijuana was pending or enacted in up to 16 states.

The researchers were not surprised to find that so-called "high-risk" groups of students, i.e., white, cigarette-smoking males, said they would be more likely to use marijuana if it were legal. However, groups of students classically considered at "low risk" for marijuana use, such as non-cigarette-smokers, religious students, those with friends who disapprove of use, said they intended to try marijuana if it were to become legal.

"What I personally find interesting is the reasonably high percentage of students who are very religious, non-cigarette smokers, non-drinkers, and those who have friends who disapprove of marijuana use-who said they intended to try marijuana if it was legal," Palamar said. "This suggests that many people may be solely avoiding use because it is illegal, not because it is 'bad' for you, or 'wrong' to use."