Historically speaking, it’s not a bad time to be the liver of a teenager. Or the lungs. Regular use of alcohol, tobacco and drugs among high school students has been on a long downward trend. In 2023, 46% of seniors said they had had a drink in the year before being interviewed; that is a precipitous drop from 88% in 1979, when the behavior peaked, according to the annual Monitoring the Future survey, a closely watched national poll of youth substance use. A similar downward trend was observed a