See, here's what bugs me. The bishops have listened to the correct science on marijuana and adolescents. They are actually in sync with the literature. 

"The current weight of evidence supports the hypothesis that early initiation of cannabis use increases the risk of early onset psychotic disorder, especially for those with a preexisting vulnerability and who have greater severity of use."

"Adolescent Initiation of Cannabis Use and Early-Onset Psychosis"

The problem is that they've shredded their cred and no one will listen.