A recent study that followed public high school students for four years has found that teens who used e-cigarettes and hookah were up to four times more likely than those who did not to use marijuana later. Richard Meich, director of Monitoring the Future, suggests that social networks play a role in this connection, as well as attitude: “You probably vaped for a while and say ‘I don’t see any problem. I’m not dropping dead. I guess it’s not as dangerous as they’re telling me it is.’ “

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