Mental health problems often begin in early childhood. However, the associations of various individual and contextual risk factors with mental health in the preschool period are incompletely understood, particularly in low- to middle-income countries (LMICs) where multiple risk factors co-exist. To address this gap, we prospectively followed 981 children in a South African birth cohort, the Drakenstein Child Health Study, assessing pre-and postnatal exposures and risk factors. The predictive value of these factors for child mental health (assessed by the Child Behavior Checklist) was modeled using structural equation modeling. We identified two key pathways to greater externalizing behavior: (1) prenatal exposure to substances (alcohol and smoking) directly predicted increased externalizing behavior (β = 0.24, p < 0.001); this relationship was partially mediated by an aspect of infant temperament (negative emotionality; β = 0.05, p = 0.016); (2) lower socioeconomic status and associated maternal prenatal depression predicted more coercive parenting, which in turn predicted increased externalizing behavior (β = 0.18, p = 0.001). Findings in this high-risk LMIC cohort cohere with research from higher income contexts, and indicate the need to introduce integrated screening and intervention strategies for maternal prenatal substance use and depression, and promoting positive parenting across the preschool period.

心理健康问题通常始于儿童早期。然而，各种个人和环境风险因素与学龄前心理健康的关联尚不完全清楚，特别是在多种风险因素共存的低收入和中等收入国家（LMIC）。为了解决这一差距，我们前瞻性地跟踪了南非出生队列 Drakenstein 儿童健康研究中的 981 名儿童，评估了产前和产后的暴露和风险因素。这些因素对儿童心理健康的预测价值（通过儿童行为检查表评估）是使用结构方程模型进行建模的。我们确定了增强外化行为的两个关键途径：（1）产前接触物质（酒精和吸烟）直接预测外化行为的增加（β = 0.24，p < 0。001）；这种关系部分是由婴儿气质的一个方面介导的（消极情绪；β = 0.05，p = 0.016）；(2) 较低的社会经济地位和相关的母亲产前抑郁症预示着更多的强制养育，这反过来又预示着外化行为的增加（β = 0.18，p = 0.001）。这个高风险中低收入国家队列的研究结果与高收入背景的研究结果一致，表明需要针对母亲产前药物使用和抑郁症引入综合筛查和干预策略，并促进整个学龄前阶段的积极养育。这反过来又预测了外化行为的增加（β = 0.18，p = 0.001）。这个高风险中低收入国家队列的研究结果与高收入背景的研究结果一致，表明需要针对母亲产前药物使用和抑郁症引入综合筛查和干预策略，并促进整个学龄前阶段的积极养育。这反过来又预测了外化行为的增加（β = 0.18，p = 0.001）。这个高风险中低收入国家队列的研究结果与高收入背景的研究结果一致，表明需要针对母亲产前药物使用和抑郁症引入综合筛查和干预策略，并促进整个学龄前阶段的积极养育。