Early life adversities and social cognition in schizophrenia

Abstract

Childhood adversity constitutes a major public health problem as it leads to numerous negative physical and mental consequences in later life. In individuals with schizophrenia, the prevalence of early life adversities (e.g. trauma, insecure attachment) is particularly high, suggesting that these negative experiences may pose a major risk factor for developing psychiatric disorders. Accumulating evidence also suggests that exposure to early life adversity, specifically trauma - defined in terms of physical, emotional and sexual abuse and physical and emotional neglect, may underlie social cognitive deficits in patients with schizophrenia. Specifically, individuals with this severe mental disorder have been consistently shown to have difficulties with understanding and inferring thoughts, emotions and feelings of oneself and others, and navigating the social world. This thesis explores the association between exposure to various childhood adversities (i.e. trauma, insecure attachment, poor parental bonding) and socio-cognitive performance, including Theory of Mind (ToM) and emotion recognition, in both individuals with schizophrenia and healthy adults, and examines possible cognitive and neural mechanisms behind these associations. The four studies included in this thesis advance the literature on the effects of childhood adversity by demonstrating that childhood trauma (specifically physical neglect and cumulative childhood trauma experiences) leads to poorer performance on ToM and emotion recognition tasks in individuals with schizophrenia and to some degree in healthy adults also. Further, the results show that better parental bonding (maternal in particular) attenuates the impact of these early life adversities on social cognitive functioning, highlighting the importance of attachment processes in social cognitive development. Additionally, this thesis provides evidence that reduced volume of the anterior cingulate cortex (ACC) may represent a neural mechanism underlying the association between early life adversity and social cognitive deficits. Lastly, the results demonstrate that chronic stress (i.e. childhood trauma) appears to have a greater impact on cognition than acute stressors. Overall, these findings highlight the need to develop new therapeutic and early intervention strategies in order to ameliorate the impact of these negative childhood experiences on brain structure and function in both clinical and non-clinical populations.