Purpose: Depression is genetically influenced, but the mechanisms that underlie these influences are largely unknown. Recently, shared genetic influences were found between depression and both cognitive ability and educational attainment (EA). Although genetic influences are often thought to represent direct biological pathways, they can also reflect indirect pathways, including modifiable environmental mediations (gene-environment-trait correlations). Here, I tested whether the genetic correlation between cognitive ability and depressive symptoms partly reflects an environmental mediation involving socioeconomic status (SES). Methods: As previously done to increase statistical power, and due to their high phenotypic and genetic correlation, EA was used as a proxy for cognitive ability. Summary statistics from a recent genome-wide association study of EA were used to calculate EA polygenic scores. Two independent samples were used: 522 non-Hispanic Caucasian university students from the Duke Neurogenetics Study (277 women, mean age 19.78, SD=1.24 years) and 5,243 white British volunteers (2,669 women, mean age 62.30, SD=7.41 years) from the UK biobank. Results: Mediation analyses in the two samples indicated that higher proxy-cognitive ability polygenic scores predicted higher SES, which in turn predicted lower depressive symptoms. Conclusion: Current findings suggest that some of the genetic correlates of depressive symptoms depend on an environmental mediation and consequently that modifying the environment, specifically through social and economic policies, can affect the genetic influences on depression. Additionally, these results suggest that findings from genetic association studies of depression may be context-contingent and reflect social, cultural, and economic processes in the examined population.

中文翻译：

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认知能力，社会经济地位和抑郁症状：基因-环境-特质的相关性

目的：抑郁症具有遗传影响，但造成这些影响的机制尚不清楚。最近，发现抑郁与认知能力和受教育程度（EA）之间存在共同的遗传影响。尽管通常认为遗传影响代表直接的生物途径，但它们也可以反映间接途径，包括可修改的环境中介（基因-环境-性状相关性）。在这里，我测试了认知能力和抑郁症状之间的遗传相关性是否部分反映了涉及社会经济地位（SES）的环境中介。方法：以前由于增加统计能力而做，并且由于它们的高表型和遗传相关性，EA被用作认知能力的代表。来自最近的EA全基因组关联研究的摘要统计数据用于计算EA多基因评分。使用了两个独立的样本：来自杜克神经遗传学研究的522名非西班牙裔白人大学生（277名女性，平均年龄19.78，SD = 1.24岁）和5,243名英国白人志愿者（2,669名女性，平均年龄62.30，SD = 7.41岁）英国生物库。结果：两个样本的中介分析表明，较高的代理认知能力多基因评分预测较高的SES，从而预测较低的抑郁症状。结论：目前的发现表明，抑郁症状的某些遗传相关性取决于环境的调节，因此，特别是通过社会和经济政策来改变环境，可能会影响抑郁症的遗传影响。另外，