With a few notable exceptions, drug use among American adolescents held steady in 1999, according to the latest results from the Monitoring the Future study, conducted at the University of Michigan Institute for Social Research (ISR). Reporting on the 25th national survey of high school seniors, and the ninth national survey of eighth- and 10th-graders, ISR research scientists Lloyd D. Johnston, Jerald G. Bachman, and Patrick M. O'Malley find that, in general, the changes in 1999 are modest.