Earlier effects on cognitive risk factors (perceived consequences of drug use, normative beliefs, resistance self-efficacy, and expectations of future use) persisted through Grade 9 in the teen leader schools; in the condition under which adults taught the lessons without teens, the prior beneficial effects on beliefs largely eroded. All of the earlier effects on actual use disappeared by Grade 9, regardless of who taught the lessons. The authors conclude that continued reinforcement of earlier lessons may be required to sustain prevention gains through the transition to high school. Footnotes, tables, figures, references