The study looked at more than 6,700 participants in the UK Biobank population cohort and found that those who reported feeling ‘hated’ as children also showed reduced volumes in two important areas of the brain: the cerebellum and the ventral striatum.
The research is published in The Journal of Child Psychology and Psychiatry. Analyses were carried out in the Dementias Platform UK (DPUK) Data Portal.
Lead author Dr Delia Gheorghe, a postdoctoral researcher based in Oxford University’s Department of Psychiatry, said: ‘We know that a substantial proportion of mental illness can be traced back to adverse experiences in childhood. However, we don’t yet fully understand the biological mechanisms behind this association. It may be, for instance, that the brain acts as a mediator in this process, and that the changes we see in brain structure following childhood trauma increase a person's vulnerability towards mental ill-health in later life.’
While numerous previous studies have shown links between various types of adversity and changes in different regions of the brain, there has been a lack of consistency and coherence across this area of research. To achieve the most beneficial results, and to help researchers fully understand the neural consequences of adversity, a number of key elements are required: larger datasets, longitudinal studies that follow participants throughout their development, and reports of adversity as it takes place (rather than retrospectively).
Dr Gheorghe said: ‘This study is of particular interest because of the statistical power involved. To be able to analyse 6,751 UK Biobank participants with survey data and brain scans is relatively unprecedented. We were therefore able to pick up subtle effects and control for multiple confound variables such as mental health status at the time when reporting adversity events, or body morphometrics at age ten, that may have influenced the results. This counters some of the limitations of having only retrospective reports of adversity and a lack of longitudinal data.’
The results show a link between survey reports of what the authors, by convention, describe as emotional abuse in childhood (‘felt hated by family member as a child’) and a reduction in volume of the cerebellum and ventral striatum brain regions – both of which play a role in emotional processes. The level of statistical rigour applied in this study means that similar effects arising from other types of adversity examined here – for example, partner abuse in adulthood – cannot be ruled out.
Dr Gheorghe added: ‘We have shown that large datasets have value in enhancing our knowledge of the links between adverse life experiences and changes in brain structure. Future studies should continue to use large samples to help build consensus – but we also need new longitudinal cohort studies to give us detailed and ongoing assessments of adversity.’
Dr Sarah Bauermeister, senior data and science manager at DPUK, is the paper’s senior author and leads a research programme on childhood adversity and brain health. Dr Bauermeister said: ‘This paper contributes valuable insights to this sensitive but important subject area, linking early adversity with later-life outcomes. Using the power of large cohort datasets, we aim to build on this research as we develop our early experience and dementia research programme in Oxford University’s Department of Psychiatry.’