Finally, some good news: A new study finds that delinquent behavior among teens is down sharply in the last decade. Fewer teens are drinking alcohol, using drugs, smoking or taking part in other illicit behaviors including stealing or fighting.

The national survey by researchers at Washington University School of Medicine in St. Louis analyzed data from more than 210,000 kids ages 12 to 17 from all 50 states between 2003 and 2014. It was sponsored by the Substance Abuse and Mental Health Administration, an agency of the U.S. Department of Health and Human Services.

The drop in substance abuse among teens parallels findings in other recent surveys, but until now no one has looked at how the drop-off may be linked to other behavioral issues.

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