Affective symptoms across the life course and the role of adverse childhood experiences

The primary aim of this thesis is to investigate the effects of single and cumulative family-related adverse childhood experiences (ACEs) on affective problems (disorders and symptoms) across the life course. Chapter 1 represents a general introduction into the prevalence, development and stability of affective problems across the life course, outlines key theories and approaches that address the development of affective problems, and highlights the role of early life risk factors in the onset and stability of these problems. Chapter 2 focuses on systematically reviewing the evidence from prospective studies for the role of single (e.g. parental divorce, parental psychopathology, childhood maltreatment unspecified, sexual abuse and family conflict) and cumulative ACEs in adult affective problems. Through synthesising effect sizes from 42 eligible studies, findings revealed that ACEs were associated with an increased risk of affective symptoms in adulthood. However the strength of the association varied, with sexual abuse, followed by cumulative adversities, being the strongest predictors of affective symptoms in adulthood. These findings show that ACEs pose risk for affective problems beyond childhood and adolescence, and that this risk may vary depending on the type and number of ACEs. Chapter 3 builds upon this work through exploring the effects of cumulative ACEs on adult affective problems by synthesising the evidence from studies that use various designs (cross-sectional, case-control, and prospective), as well as critically evaluating methodological strengths and limitations of the existing studies, and suggesting new directions for future research. Future studies would benefit from more systematic assessments of ACEs using prospective multi-informant reports, and from utilisation of a developmentally sensitive life course approach to affective symptoms. Chapter 4 and Chapter 5 extend existing research by utilising longitudinal prospectively collected data from the Medical Research Council (MRC) National Survey of Health and Development (NSHD). These two empirical studies make a novel contribution to the research field by modelling life course profiles of affective symptoms across a period of more than 50 years (from age 13 through 69), and by investigating the effects of single and cumulative ACEs on affective symptoms across the lifespan. As demonstrated in Chapter 4, a higher cumulative ACE score was associated with affective symptom severity in late adulthood (i.e., at ages 60-64 and 69), but not at earlier ages (i.e., at ages 13, 15, 36, 43, 53). This unexpected finding indicates that the risk of affective symptoms in those who experienced multiple ACEs persists beyond childhood and adolescence, up to late adulthood. Further research is encouraged to explore the effect of cumulative ACEs on affective symptoms across the lifespan using person-centred approaches and to explore risk and resilience mechanisms underlying the association. In Chapter 5, advanced modelling techniques – latent class analysis (LCA) – were employed to derive life course profiles of affective symptoms, and the effects of 24 single ACEs and their accumulation, in relation to these life course profiles, were investigated. Four life course profiles of affective symptoms were identified: no symptoms, adolescent symptoms only, adult symptoms only, and adolescent and adult symptoms. Four ACEs were significantly associated with affective symptom trajectories, with small effect sizes observed: childhood chronic illness was associated with adult symptoms only; whereas growing up in an overcrowded house and parental poor perceived health were associated with symptoms in adolescence and adulthood. However, no associations were found for twenty of the ACEs tested. The thesis concludes with the Discussion, which aims to synthesise and summarise the evidence from each study, discuss their key findings and implications, before acknowledging the strengths and limitations of the research area in general, along with providing some suggestions for future research.