"• Hispanics now have the highest annual prevalence for crack and cocaine at all three grade levels. The prevalence of cocaine for Hispanic students has tended to be high compared to the other two racial/ethnic groups, particularly in the lower grades. It bears repeating that Hispanics have a considerably higher dropout rate than Whites or African Americans, based on Census Bureau statistics, which should tend to diminish any such differences by 12th grade, yet there remain sizeable differences in the upper grades.

"• An examination of racial/ethnic comparisons at lower grade levels shows Hispanics having higher levels of use of many of the substances on which they have the highest levels of use in 12th grade, as well as for several other drugs. For example, in 2015, other cocaine (i.e., powder cocaine) had a lifetime prevalence in 8th grade for Hispanics, Whites, and African Americans of 2.0%, 0.9%, and 0.9%, respectively. In fact, in 8th grade -- before most dropping out occurs -- Hispanics had the highest levels of use of almost all substances, whereas by 12th-grade Whites have the highest levels of use of most. Certainly the considerably higher dropout rate among Hispanics could help explain this shift, and it may be the most plausible explanation. Another explanation worth consideration is that Hispanics may tend to start using drugs at a younger age, but Whites overtake them at older ages. These explanations are not mutually exclusive, of course, and to some degree both explanations may hold true.14"

Source

Miech, R. A., Johnston, L. D., O’Malley, P. M., Bachman, J. G., & Schulenberg, J. E. (2016). Monitoring the Future national survey results on drug use, 1975–2015: Volume I, Secondary school students. Ann Arbor: Institute for Social Research, The University of Michigan. Pages 109-110.