Marty Walsh in The Boston Globe

On Drugs: Don't legalize marijuana: it's unsafe & lowers IQ in kids

Where marijuana is legal, young people are more likely to use it: while use among minors has declined nationwide in recent years, states like Colorado have seen an increase. Kids in states that have legalized marijuana have easier access to the drug. And many believe that, since the drug is legal for adults, it must be safe to use.

What the evidence shows us, though, is that marijuana is not safe. Regular use that starts in adolescence has been shown to impair brain development, and even lower IQ. And increasingly, medical science is also showing a frightening correlation between regular marijuana use and severe mental health issues.