Teens who view advertising for medical marijuana are more likely to report using the substance or plan to use it in the future, a new study has found.
The study analysed more than 8,000 Southern California middle school students and found that youth who reported seeing any ads for medical marijuana were twice as likely as peers who reported never seeing an ad to have used marijuana or report higher intentions to use the drug in the future.
Researchers said the study - the first to explore a link between marijuana advertising and youth behaviour - still cannot directly address whether seeing ads cause marijuana use.
However, the study raises questions about whether there is a need to revise prevention programming for youth as the availability, visibility and legalisation surrounding marijuana changes, the researchers said.
"As prohibitions on marijuana ease and sales of marijuana become more visible, it's important to think about how we need to change the way we talk to young people about the risks posed by the drug," said lead author Elizabeth D'Amico, senior behavioural scientist at RAND (Research And Development) Corporation, a nonprofit research organisation.
"The lessons we have learned from alcohol - a substance that is legal, but not necessarily safe - may provide guidance about approaches we need to take toward marijuana," she said.
RAND researchers analysed information collected from 8,214 students enrolled in 6th, 7th and 8th grade who attended 16 Southern California middle schools during 2010 and 2011.
The students were asked each year about exposure to medical marijuana advertising, marijuana use and their intentions about whether to use marijuana in the future.
During the first survey, 22 per cent of the students reported seeing at least one advertisement for medical marijuana over the past three months and the rate jumped to 30 per cent the following year.
Seeing advertisements for medical marijuana was related to middle school adolescents' intentions to use marijuana and their actual marijuana use one year later.
Researchers said this is particularly important given that the mean age of adolescents surveyed was 13 and initiation of marijuana use during early adolescence is associated with poor school performance, neuropsychological performance deficits and further use of other illicit drugs, such as heroin and cocaine.
Researchers said they could not determine whether adolescents who were predisposed to use marijuana paid more attention to marijuana advertising or whether the advertising may have influenced adolescents' attitudes toward the drug.
"Given that advertising typically tells only one side of the story, prevention efforts must begin to better educate youth about how medical marijuana is used, while also emphasising the negative effects that marijuana can have on the brain and performance," D'Amico said.
The study was published in the journal Psychology of Addictive Behaviors.
