Purpose: To evaluate the effect of a violence prevention curriculum an
d of trained peer leaders on self-reported aggressive behaviors, knowl
edge about violence and conflict-resolution skills, self-efficacy, and
attitudes among 223 6th graders. Methods: The effect of two intervent
ion groups (violence prevention curriculum taught by the teacher with
or without the assistance of trained peer leaders) and one control gro
up were compared. Ten 6th grade classes (four control and six interven
tion classes) of four middle schools participated in the study. Studen
ts were evaluated before and shortly after the implementation of the c
urriculum, as well as 3 months later. Results: The intervention reduce
d self-reported aggressive behaviors among boys, but this reduction wa
s significant only in two of the six intervention classes. Both interv
entions had an overall significant effect on increasing knowledge abou
t violence and skills to reduce violence. After the intervention, stud
ents also developed a more negative attitude toward responding violent
ly when provoked. Attitude change was stronger among students from the
teacher plus peer leader group. No intervention effect was observed o
n self-efficacy nor on attitudes toward skills to reduce violence. Cha
nges were not maintained over time. Conclusions: Results emphasize the
need for continuous and comprehensive interventions, follow-up evalua
tions, and careful selection of peer leaders. Aggressive behaviors, no
t knowledge alone, should be used as the main dependent variable.