A new study finds marijuana use among young teens is on the decline, while disapproval of the drug among this age group is increasing. Marijuana use is also on the decline among teens ages 15 to 17.

The study examined marijuana use among teens from 2002 to 2013, Yahoo Parenting reports. The researchers from the University of Texas at Austin found the proportion of 12- to 14-year-olds who strongly disapproved of starting to use marijuana increased from 74.4 percent to 78.9 percent. Among that age group, past-year marijuana use decreased from 6 percent in 2002 to 4.5 percent in 2013.

Among teens ages 15 to 17, disapproval of marijuana use did not change, but marijuana use declined from 26 percent to 22 percent during that same time period.

The findings, based on questionnaires from about 500,000 teens and young adults, appear in The American Journal of Drug and Alcohol Abuse.

“With decriminalization, medicalization and in some places recreational use, and adults no longer viewing marijuana use as an immoral act, we were concerned how it would affect teen use and attitudes,” said lead author Christopher Salas-Wright. “But, especially at the middle school age, youth became more disapproving, not more permissive. And certainly this data tells us we don’t see a dramatic spike at the national level in terms of marijuana use.”

The findings indicate that the growing number of states legalizing marijuana “have not resulted in more use or greater approval of marijuana use among younger adolescents,” Salas-Wright said in a news release.

He added the study provided a national overview, but did not give insights into states such as Colorado and Washington, which have legalized recreational marijuana for adults 21 and older.

Young adults ages 18 to 25 were less likely to disapprove of marijuana use in 2013 compared with 2002, but the study found no corresponding spike in marijuana use among this age group.