The present study investigated how intervention might alter the relationship between perpetrating violence and later drug use. A cluster-randomized controlled trial design involving 72 schools (38 intervention, 34 control) and 6390 students attending grades 7 and 8 was employed in Brazil. Drug use and violence were assessed at three points. A random-intercept cross-lagged panel model examined the reciprocal association between drug use and school violence domains across the three data collection waves. For both groups, we found that the cross-lagged effect of perpetration on further drug use in adolescents was stronger than the reverse, but the interrelationship was not statistically significant between #Tamojunto and control schools. The carry-over effects of drug use and violence were also not significantly different between groups. There is a lack of evidence showing that #Tamojunto can modify the dynamics between drug use and school violence across the 21-month period. The direction of the causal effect (i.e., the more perpetration behavior, the more subsequent drug use behavior) is present, but weak in both groups. The trial registration protocol at the national Brazilian Register of Clinical Trials (REBEC) is #RBR-4mnv5g.

本研究调查了干预如何改变实施暴力与后来吸毒之间的关系。一项整群随机对照试验设计涉及 72 所学校（38 所干预学校，34 所对照学校）和 6390 名 7 年级和 8 年级的学生。吸毒和暴力在三个方面进行了评估。随机截距交叉滞后面板模型检查了三个数据收集浪潮中吸毒和校园暴力领域之间的相互关联。对于这两个群体，我们发现犯罪行为对青少年进一步吸毒的交叉滞后效应强于反向效应，但#Tamojunto 和对照学校之间的相互关系在统计学上不显着。吸毒和暴力的遗留影响在各组之间也没有显着差异。缺乏证据表明#Tamojunto 可以在 21 个月内改变吸毒与校园暴力之间的动态关系。因果效应的方向（即实施行为越多，随后的吸毒行为越多）存在，但在两组中都很弱。巴西国家临床试验注册中心 (REBEC) 的试验注册协议为#RBR-4mnv5g。