Swipe left or right to scroll. Monitoring the Future Study: Trends in Prevalence of Synthetic Marijuana (K2/Spice) for 8th Graders, 10th Graders, and 12th Graders; 2020 (in percent)* Drug Time Period 8th Graders 10th Graders 12th Graders Synthetic Marijuana (K2/Spice) Past Year [1.6] 2.5 2.4 February 11, 2020