Despite laws against advertising cannabis to teens, young people reported in surveys that they still see a lot of positive cannabis messages through social media posts.

Washington State University researchers found these messages were also connected to the teens' intentions to use cannabis, and for college students, with their actual use. Anti-cannabis messages also had an effect in lessening use-intentions, but young people saw less of those types of messages.

"Youth, in particular, have really grown up bombarded with cannabis information compared to previous generations," said Jessica Willoughby, first author on the study published in the journal Health Communication and an associate professor in WSU's Murrow College of Communication. "We found that they were seeing more positive messages about using cannabis and a lot less about the risks."

For this study, the researchers surveyed 350 teens and 966 college students from across Washington state, where recreational marijuana has been legal since 2012.

The state does have regulations aimed at preventing advertising cannabis to minors, such as prohibiting the use of cartoons or youth-oriented celebrities. This does not prevent individuals from posting about cannabis on social media, however.

Of the study participants, the vast majority, over 80%, reported seeing pro-cannabis messages on social media, such as posts about being high or claims that marijuana is harmless. The pro-cannabis messages most often encountered were those from celebrities or lyrics in songs.

"Parents might not understand that if their kid is using a social media site—whether it's Twitter, YouTube, Instagram, Facebook or Snapchat —they are going to see cannabis messages. That's just the reality," said co-author Stacey Hust, a professor at WSU's Murrow College of Communication. "This means we need to be getting training into schools at much younger ages. At the very least middle school and high school health classes need to talk about cannabis and how it can be harmful to the developing brain."

The study participants also reported seeing some anti-cannabis messages, such as that cannabis can cause harm or that smoking it is gross or for losers, but they saw these types of messages less often than pro-cannabis ones.

The youth, both teens and college students, who reported seeing higher levels of positive messages were more likely to indicate an intention to use cannabis. The college students were also asked about actual use and there was a positive connection between exposure to pro-cannabis posts and use for that group.

The good news is that seeing the anti-cannabis messages had some effect, although indirectly. Among the youth who already held beliefs that cannabis use could cause negative outcomes, such as damaging their brain or doing worse in school, seeing anti-cannabis messages appeared to lower their intentions to use.

The researchers said this finding indicates a good area for parents and counselors to target.

"Prevention efforts can have an impact," said Willoughby. "Since youth are seeing more of that positive cannabis content, it's worthwhile to put out more content highlighting the risks, especially to the young people like them."