A study from the Keck School of Medicine of USC found that California high school students who frequently saw cannabis and e-cigarette posts on social media, particularly TikTok, were more likely to start using these substances. The research indicated a significant link between exposure to such content and increased substance use, even as overall e-cigarette use among teens is declining. Influencer content, which often bypasses regulatory scrutiny, poses additional risks by normalizing cannabis and e-cigarette use among young audiences.