Relative Genetic and Environmental Influences on Self-Harm and Depression

人际暴力影响着全世界数百万人。世界卫生组织将其定义为“故意使用武力或武力，威胁或实际，对另一个人，导致或极有可能导致伤害、死亡、心理伤害、发育不良或剥夺”。这包括儿童虐待、欺凌、亲密伴侣暴力和性暴力。暴露于这些形式的人际暴力是青春期和成年期一系列负面心理健康结果的确定风险因素，包括抑郁和自残（非自杀和自杀）。除了环境风险之外，这些心理健康结果还受到遗传效应的影响。假设遗传影响不仅有直接影响，而且与环境相互作用（基因型-环境相互作用）。基因-环境相互作用通常在素质-压力框架内解释，据此假设，与遗传易感性较低的人相比，那些对精神健康困难具有高遗传易感性的人在暴露于消极环境后更有可能发展为精神健康障碍。它也可以在差异易感性框架内解释，这表明一些人有对环境做出反应的倾向，部分原因是遗传差异，这些人更有可能受到消极和积极环境的影响。就心理健康而言，这意味着环境敏感性较高的人更有可能在负面接触（如人际暴力）后出现心理健康问题。在本博士课程中，自残和抑郁的病因学及其与人际暴力的关系将使用遗传信息设计进行研究，使用来自英国、斯里兰卡和加拿大的纵向数据，以及来自双胞胎早期发展研究（TEDS）、科伦坡双胞胎和单胎研究（COTASS）和魁北克儿童发展纵向研究（QLSCD）的更具体数据。心理健康和人际暴力是全球性问题，因此，使用来自三个不同国家的数据集，包括一个中低收入国家的数据集，将有助于这项研究更具普遍性。分析将包括双胞胎模型和结合多基因分数的线性模型。这些项目将纳入社区参与和参与，以确保成果与受研究影响的人相关。由于学生作为欧洲白人的地位，这将与涉及斯里兰卡数据集的项目特别相关，因此将通过对斯里兰卡的实地考察来实现有意义的社区参与。此次访问的目的是与斯里兰卡的利益攸关方开展一项参与活动（例如，研讨会），为这项研究提供信息，并将结果传达给那些参与支持遭受人际暴力的个人的人。这将有助于确定该研究在斯里兰卡产生积极社会影响的最有效方式。

Interpersonal violence affects millions of people worldwide. The WHO defines it as the "intentional use of physical force or power, threatened or actual, against another person, which either results in or has a high likelihood of resulting in injury, death, psychological harm, maldevelopment, or deprivation". This includes childhood maltreatment, bullying, intimate partner violence (IPV), and sexual violence. Exposure to these forms of interpersonal violence is an established risk factor for an array of negative mental health outcomes during adolescence and adulthood, including depression and self-harm (non-suicidal and suicidal). Beyond environmental risks, these mental health outcomes are also influenced by genetic effects. Genetic influences are hypothesised not only to have direct effect but to interact with the environment (Genotype-environment interaction). Gene-environment interaction is often interpreted within the Diathesis-Stress framework whereby it is hypothesised that those who have high genetic predisposition to mental health difficulties will be more likely to develop a mental health disorder after exposure to a negative environment, compared to those with lower genetic predisposition. It can also be interpreted within the Differential Susceptibility framework, which suggests that some people have a predisposition to responding to the environment, explained partly by genetic differences, and those people will be more likely to be affected by exposures to negative as well as positive environments. In the case of mental health, it means that people with higher environmental susceptibility will be more likely to develop mental health difficulties following negative exposures, such as interpersonal violence.In this PhD, the aetiology of self-harm and depression, and their relationship with interpersonal violence will be studied using genetically informed designs, with longitudinal data from the UK, Sri Lanka and Canada, and more specifically data from the Twins Early Development Study (TEDS), Colombo Twin and Singleton Study (COTASS), and Quebec Longitudinal Study of Child Development (QLSCD). Mental health and interpersonal violence are global issues, therefore using datasets from three different countries, including a lower-middle income country, will contribute to this research being more generalisable. Analyses will include twin modelling and linear models incorporating polygenic scores. The projects will incorporate community engagement and involvement ito ensure outcomes are relevant to the people affected by the research. Due to the student's positionality as a white European, this will be particularly relevant for the project involving the dataset from Sri Lanka, whereby meaningful community engagement will be achieved through a fieldwork visit to Sri Lanka. The aim of this visit will be to conduct an engagement activity (e.g., workshop) with stakeholders in Sri Lanka to inform this piece of research and to communicate the results to those involved in supporting individuals exposed to interpersonal violence. This will contribute to identifying the most effective way for the research to have a positive social impact in Sri Lanka.