Data extraction.

Background
Anxiety and depression are on the rise among children and adolescents globally. Low- and middle-income countries (LMICs) face heightened vulnerability due to limited resources, restricted access to mental health services, socioeconomic disparities and widespread mental health stigma. Schools offer a unique and potentially impactful setting for preventive interventions targeting anxiety and depression in young individuals.
Aim
We aimed to identify empirical research to explore the effectiveness of school-based interventions designed to prevent anxiety and depression among children and adolescents in LMICs.
Method
Ovid MEDLINE, Embase, PsycINFO and CENTRAL were systematically searched for articles published between 2018 and July 2023. Randomised controlled trials that evaluated school-based interventions for children and adolescents aged 4–18 years in LMICs were included. Only studies in English language were included. The primary outcomes were anxiety and/or depressive symptoms. Risk-of-bias assessments were performed.
Results
Out of 3863 articles identified, six studies comprising 1587 students met the inclusion criteria. Among the four studies that examined interventions for the prevention of both anxiety and depression, as well as anxiety alone, only one study showed a reduction in anxiety symptoms. In the case of depression, three out of four studies reported improvements in depressive symptoms. The finding suggests a potential effectiveness of preventive interventions against depression, but not anxiety. However, this finding should be interpreted with caution given the limited number of studies identified. All studies were either classified as high risk of bias or having some concerns.
Conclusion
There is some evidence of the effectiveness of school-based interventions in preventing anxiety and depression among young people in LMICs. Further research is necessary to gain a more comprehensive understanding of this critical issue. Moving forward, it is crucial to enhance and broaden existing school-based prevention programs in these nations, exploring different intervention strategies tailored to their specific contextual factors.

背景
全球范围内，儿童与青少年的焦虑与抑郁症状呈上升趋势。中低收入国家（Low- and middle-income countries, LMICs）由于资源匮乏、精神卫生服务获取渠道受限、社会经济差异显著以及普遍存在的精神卫生污名化问题，面临着更高的心理健康脆弱性。校园为针对青少年群体的焦虑与抑郁预防性干预措施提供了独特且极具潜力的实施场景。

研究目的
本研究旨在检索相关实证研究，以探讨针对中低收入国家（LMICs）儿童青少年的校园式焦虑与抑郁预防干预措施的有效性。

研究方法
系统检索Ovid MEDLINE、Embase、PsycINFO及CENTRAL数据库，筛选2018年至2023年7月期间发表的文献。纳入针对中低收入国家（LMICs）4~18岁儿童青少年的校园干预措施评估随机对照试验，且仅纳入英文文献。本研究的主要结局指标为焦虑症状和/或抑郁症状，并开展偏倚风险评估。

研究结果
共检索到3863篇文献，最终有6项涵盖1587名学生的研究符合纳入标准。在4项评估同时针对焦虑与抑郁、或仅针对焦虑的预防干预的研究中，仅1项研究显示焦虑症状有所减轻。针对抑郁的4项研究中，有3项报告了抑郁症状的改善。该结果提示预防性干预措施或可有效改善抑郁症状，但对焦虑症状的预防效果未显现出一致性获益。不过，鉴于纳入研究数量有限，对该结果的解读需谨慎。所有研究均被评定为高偏倚风险或存在一定偏倚风险隐患。

研究结论
现有证据表明，中低收入国家（LMICs）的校园式干预措施可在一定程度上有效预防儿童青少年的焦虑与抑郁症状。仍需开展更多研究以全面厘清这一关键公共卫生议题。未来亟需优化并拓展这些国家现有的校园预防项目，探索适配其特定情境因素的多样化干预策略。