IMPORTANCE Individual-level social support protects against major depressive disorder (MDD) among adults exposed to trauma. Little is known about the consequences of community-level interventions in the general population. OBJECTIVE To determine the potential consequences of neighborhood social infrastructure on incident MDD in a high-risk general population. DESIGN, SETTING, AND PARTICIPANTS This longitudinal, multilevel study estimated associations between a neighborhood-level program in a case-control design and subsequent individual outcomes across 10 years (2006-2015) in a cohort of young adults. Exogenously placed social programs simulate natural experiment conditions in a high-poverty population experiencing armed conflict (1998-2006). The western Chitwan valley in Nepal has a general population at high risk of MDD, with neighborhoods exposed to interventions to improve social support. From a random sample (response rate 93%) selected to represent the general population in 2016, participants aged 25 to 34 years in 2006 were studied. These individuals resided within 149 neighborhoods that varied in their availability of active social support programs. The analyses were conducted between October 2020 and November 2021. EXPOSURES The Small Farmers Development Program (SFDP) uses shared, joint liability financial credit among neighbors to build social capital and cohesion within neighborhoods. MAIN OUTCOMES AND MEASURES Onset of DSM-IV MDD after the conflict, assessed by the Nepal-specific, clinically validated World Mental Health Composite International Diagnostic Interview with a life history calendar. The hypothesis tested was that exposure to SFDP reduced adult onset of MDD. RESULTS Of the 1917 survey participants, 886 (46.2%) were women, and 856 (44.7%) were of Brahmin or Chhetri ethnicity. Of the 149 neighborhoods, 21 had an active SFDP group, and 156 of 1917 (8.1%) participants experienced MDD between 2006 and 2015. Discrete-time hazard models showed participants living in neighborhoods with an SFDP experienced incident MDD at nearly half the rate as others (odds ratio = 0.55; 95% CI, 0.30-1.02; P = .06). A multivariate, multilevel matching analysis showed the incidence of MDD among adults living in neighborhoods with an SFDP was 19 of 256 (7.4%), compared with 33 of 256 (12.9%) in the matched sample with no SFDP (z = 2.05; P = .04). CONCLUSIONS AND RELEVANCE Living in a neighborhood with community-level social support infrastructure was associated with reduced subsequent rates of adult-onset MDD, even in this high-risk population. Investments in such infrastructure may reduce population-level MDD, supporting clinical focus on potentially unpreventable cases.

中文翻译：

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南亚冲突后环境中的社区级社会支持基础设施和严重抑郁症的成人发病。

重要性 个人层面的社会支持可以防止遭受创伤的成年人患重度抑郁症 (MDD)。人们对社区一级干预措施对普通人群的影响知之甚少。目的 确定社区社会基础设施对高危人群 MDD 事件的潜在影响。设计、设置和参与者 这项纵向、多层次的研究评估了病例对照设计中的社区级计划与随后 10 年（2006-2015 年）年轻人队列中的个人结果之间的关联。外生的社会计划模拟了经历武装冲突的高度贫困人口的自然实验条件（1998-2006）。尼泊尔西部奇特旺山谷的普通人群患重度抑郁症的风险很高，社区需要采取干预措施来改善社会支持。从 2016 年代表一般人群的随机样本（答复率为 93%）中，对 2006 年年龄在 25 至 34 岁的参与者进行了研究。这些人居住在 149 个社区，这些社区的积极社会支持计划的可用性各不相同。这些分析是在 2020 年 10 月至 2021 年 11 月期间进行的。 风险 小农发展计划 (SFDP) 利用邻居之间共享的连带责任金融信贷来建立社会资本和社区内的凝聚力。主要成果和措施 冲突后 DSM-IV MDD 的发作，通过针对尼泊尔的、经过临床验证的世界精神卫生综合国际诊断访谈和生活史日历进行评估。测试的假设是，接触 SFDP 可减少成年 MDD 的发病率。结果 在 1917 名调查参与者中，886 名 (46.2%) 为女性，856 名 (44.7%) 为婆罗门或切特里族。在 149 个社区中，21 个拥有活跃的 SFDP 小组，2006 年至 2015 年间，1917 名参与者中有 156 名 (8.1%) 经历过 MDD。离散时间危险模型显示，居住在有 SFDP 社区的参与者经历 MDD 事件的比率几乎是 SFDP 社区的一半。其他（优势比 = 0.55；95% CI，0.30-1.02；P = .06）。多变量、多水平匹配分析显示，生活在有 SFDP 社区的成年人中，MDD 的发病率为 256 人中的 19 人 (7.4%)，而在没有 SFDP 的匹配样本中，256 人中有 33 人 (12.9%) (z = 2.05；P = .04)。结论和相关性 生活在拥有社区级社会支持基础设施的社区与成人发病性 MDD 发病率降低相关，即使在这一高危人群中也是如此。对此类基础设施的投资可能会减少人口层面的 MDD，支持临床重点关注潜在的无法预防的病例。