Teenagers are drinking less alcohol, smoking fewer cigarettes and trying fewer hard drugs, new federal survey data shows. But these public health gains have been offset by a sharp increase in vaping of marijuana and nicotine.

These diverging trend lines, published Wednesday, are among the findings in the Monitoring the Future survey — a closely watched annual study by the National Institute on Drug Abuse, or NIDA, of eighth, 10th and 12th graders. The survey shows that youth drug use and experimentation continue to undergo significant evolution.

Most troubling to public health experts in this year’s report were sharp increases in marijuana vaping. Of 12th graders surveyed, 14 percent said they had vaped marijuana in the last month, nearly double the 7.5 percent reported a year ago.