Neurobiological pathways from trauma exposure to child mental health outcomes in a high adversity South African Birth Cohort

Children growing up in many low and middle income country (LMIC) contexts are at high risk of exposure to trauma, such as domestic or community violence, child abuse, or severe injury. Exposure to such adversity has been identified as a major contributor to psychological disorders in children. The negative impacts of childhood trauma exposure have been found to persist into adulthood, with wide ranging individual and societal consequences. Indeed, individuals exposed to childhood trauma are disproportionately represented among the most vulnerable groups in societies worldwide (e.g., the homeless). Despite this robust evidence of the detrimental effects of trauma exposure, there are key limitations to our understanding of this problem. First, the majority of relevant evidence derives from high income countries, rather than from LMICs, where exposure to childhood trauma is substantially more common and many children experience multiple adversities. Consequently, we have limited knowledge of the impact of childhood trauma as experienced in the types of contexts in which the majority of the world's children live. This, in turn, undermines capacity for targeted prevention or intervention in such settings. Second, there is extremely limited understanding of the underlying mechanisms that link early trauma with negative mental health outcomes, particularly considering biological processes. Our understanding of how trauma becomes embedded in the brain and body in children, and how that, in turn, confers risk of multiple psychological disorders, is particularly limited.
We plan to address limitations in our understanding of the mental health consequences of trauma in children through capitalizing on and extending a key South African birth cohort, the Drakenstein Child Health Study (DCHS). Childhood trauma is a major mental health related concern in South Africa, particularly due to high levels of interpersonal violence (including high rates of community violence, intimate partner violence and child maltreatment). We propose to conduct an in depth study of the mental health impacts of childhood trauma in this cohort, which will address limitations in our understanding and achieve a major change in knowledge in an area of key importance for LMIC contexts. The DCHS is exceptional in having repeatedly measured child trauma exposure during the first years of life, and having simultaneously completed biological assessments and measures of child mental health at multiple times points. High rates of trauma exposure among children in the DCHS mean that it provides an opportunity to study the impact of childhood trauma which is not afforded by birth cohorts based in high income country contexts, in which very few children are exposed to severe or recurrent trauma. We plan to follow-up children in the DCHS cohort at age 8-9 years, when many common psychological disorders manifest for the first time in children. Because we have measures of both exposure to trauma and biological processes which are repeated over time, we will be able to understand how trauma influences stress-related biological systems, and how those effects, in turn, may lead to psychological disorder in children. We will be able to study key biological systems involved in the body's response to stress, the immune system (which is increasingly being understood to be closely related to stress), and brain development. Through identifying pathways from trauma to psychological disorders in children, this work may change the way we provide interventions in the future.

Children growing up in many low and middle income country (LMIC) contexts are at high risk of exposure to trauma, which has been identified as a major determinant of poor mental health, accounting for as much as 47% of the overall risk for psychological disorders in children, and has been linked to adverse physical health outcomes. Despite such evidence, there are key limitations to our knowledge in this area. The majority of relevant data derives from high income countries, rather than from LMICs, where exposure to childhood trauma is substantially more common and many children experience multiple adversities. Consequently, we have limited knowledge of trauma as experienced in the types of contexts in which the majority of the world's children live. Moreover, there is extremely limited understanding of the underlying etiological mechanisms, particularly considering neurobiological factors. The mechanisms via which childhood trauma leads to a range of different psychological disorders are particularly poorly studied. We propose to address limitations in our understanding of the consequences of trauma exposure in children through capitalizing on and the Drakenstein Child Health Study (DCHS), a longitudinal South African birth cohort that includes measurement of child trauma from age 2-6 years, with mental health and psychobiological processes being simultaneously assessed. We will complete comprehensive assessments of trauma exposure mental health at 8-9 years in the DCHS, and conduct in-depth analyses of neurobiological pathways from trauma exposure to disorder, studying markers related to stress responding, inflammation, and brain structure. The high prevalence of trauma in the cohort, and the availability of repeated measures of exposure, mental health, and neurobiological mediators will allow us to probe causal effects in a way that has not previously been possible.

The proposed project will yield much needed information about risk of adverse mental health outcomes following trauma exposure among children in a LMIC context; and the factors that contribute to or help to mitigate against that risk. It has the potential to achieve impact as follows.
1) Raising awareness of trauma related mental health problems in children amongst local stakeholders and the wider public.
Grant activities have the potential to raise awareness of the impacts of trauma, within and outside of the home, on child well-being in focal communities and among the wider public. We will work to achieve this impact through public engagement activities that are already a standard part of the DCHS, including via a public-participant engagement group, regular community feedback sessions, engagement with local services, and online resources, including a study website and relevant online communication tools (e.g., Facebook, Twitter accounts). We will produce summary reports detailing key findings and their implications that are accessible to a range of audiences, and will share these with key relevant community, clinical and third sector organisations through existing links. We will also engage with the media to share findings, both in South Africa in the UK, to ensure wider reach. Team members have previous, documented experience of excellent media engagement.
2) Guiding trauma-informed clinical practice and contributing to novel intervention development
The proposed project will provide key information about the likely contribution of trauma exposure to a range of mental health problems, which is relevant to how mental disorders in children are understood and treated. As such, we will prioritize communication with clinical audiences in all of the engagement activities outlined. In addition, research findings could inform the development of intervention targets for trauma exposed children experiencing mental health problems. Will ensure the study achieves its full potential in this regard, by developing a detailed framework for developing any potential clinical applications in the final year of the project, augmented by stakeholder and scientific engagement activities.
3) Informing public policy related to screening, prevention and intervention
Raising awareness of risk factors for adverse mental health outcomes in children exposed to trauma can potentially inform policy with respect to screening, prevention and intervention. As a team, we are well placed to ensure that study findings are communicated to policy makers, due to established links with policy groups and inputs into national guidelines, policy documents and consultations. We will utilise such capacity within our team in order to ensure that any policy relevant outputs from our research are shared effectively.
4) Broader scientific capacity building, through a) establishing a unique mental health resource; and b) building capacity in advanced quantitative analysis, a priority skills gap in South Africa.
We will establish an important data resource which will be suitable for data sharing. We will work to maximise this potentially important impact through the academic dissemination plan already outlined, coupled with targeted engagement of academics in the field, including through a focused workshop in the final year of the study. We will also build research capacity in advanced data analytic methods, which will be particularly important for the South African team and wider research community, due to a critical lack of this essential skill set in the region. We have built in training and appropriate supervision of early career researchers on the project in order to achieve this.