Sexual risk behaviors are closely related to the use of alcohol, tobacco, and other illicit drugs as well as teen dating violence. School-based drug prevention programs that teach social and personal skills could potentially also reduce sexual risk behaviors. We examined the effects of the #Tamojunto program on youth sexual risk behaviors. A randomized controlled trial was conducted with 6391 7th and 8th grade students in 72 public schools in six Brazilian cities. Baseline data were collected prior to program implementation. Two waves of follow-up assessments occurred after 9 and 21 months. Analyses were performed taking into account the multilevel structure of the data. We used intention-to-treat to evaluate changes in the prevalence of sexual risk behaviors over time and between groups. Adolescent age ranged from 11 to 15 years, with a mean of 12.6 ± 0.8 years, and 51.0% were female. Among all participants, receipt of #Tamojunto was associated with higher risk of lifetime sex at 21 months follow-up (OR 1.27, 95% CI [1.03, 1.56]). Among girls, at 9 months follow-up, the program was associated with higher likelihood of having engaged in sex in the last month (OR 1.76, 95% CI [1.13, 2.74]). At 21 months follow-up, girls receiving the program were more likely to report engaging in condomless sex in the last month (OR 1.64, 95% CI [1.07, 2.50]). #Tamojunto may be ineffective and possibly harmful for preventing sexual risk behaviors, especially among girls. We suggest further investigation of the possible mediating role of life skills intervention components on girl’s sexual behaviors.

性风险行为与使用酒精、烟草和其他非法药物以及青少年约会暴力密切相关。教授社会和个人技能的学校毒品预防计划也可能减少性风险行为。我们检查了#Tamojunto的影响青少年性风险行为计划。一项随机对照试验在巴西六个城市的 72 所公立学校的 6391 名 7 和 8 年级学生中进行。在计划实施之前收集基线数据。9 个月和 21 个月后发生了两波后续评估。进行分析时考虑了数据的多级结构。我们使用意向治疗来评估性风险行为流行率随时间和组间的变化。青少年年龄范围为 11 至 15 岁，平均为 12.6 ± 0.8 岁，51.0% 为女性。在所有参与者中，收到#Tamojunto与 21 个月随访时终生性行为的较高风险相关（OR 1.27, 95% CI [1.03, 1.56]）。在女孩中，在 9 个月的随访中，该计划与上个月发生性行为的更高可能性相关（OR 1.76, 95% CI [1.13, 2.74]）。在 21 个月的随访中，接受该计划的女孩更有可能报告在上个月进行无安全套性行为（OR 1.64, 95% CI [1.07, 2.50]）。#Tamojunto可能对预防性风险行为无效且可能有害，尤其是在女孩中。我们建议进一步调查生活技能干预成分对女孩性行为可能的中介作用。