Investigation in the relationship between childhood adversity and cognitive function in psychosis and individuals at clinical high risk of psychosis

Abstract

Background An increasing body of research is suggesting that childhood trauma and adversity may be associated with various adverse mental health outcomes, including psychosis. Cognitive functioning is often compromised in psychosis, and research has shown that there may be a link between early trauma and cognitive impairment in people with psychosis. No systematic review of the literature of this link has been undertaken, and very few studies have examined samples of individuals at high clinical risk for psychosis, to assess whether the potential link between adversity and cognitive functioning exists, without the confounding factors of length of illness, antipsychotic medication and chronicity of symptoms. Method The systematic review of all relevant electronic databases investigates the research to date on the association between childhood adverse experiences and cognitive ability in psychosis, and the conclusions that can be drawn from the existing literature, taking into account relevant considerations regarding sample, methodology and statistical analysis. The subsequent empirical study utilizes a sample at clinical high risk of developing psychosis, and a healthy control group to investigate whether any putative association in specific domains of cognitive functioning, or global cognitive ability and childhood adversity exist in those at clinical high risk, compared to controls. Results The systematic review indicated that at present, the literature looking into childhood adversity and cognitive ability in relation to psychosis is heterogeneous, with some studies finding that this association only occurs in patients, whilst others suggest it only occurs in the control groups. Some studies found it to be specific to certain cognitive domains, whilst others suggest it was a more global impairment. Methodology, samples and analysis differed considerably across studies, and likely contribute to the heterogeneity of the literature. The empirical paper showed a significant interaction effect between group (high risk versus controls) in the high childhood adversity group, in relation to global cognitive ability. Interestingly, this was not related to psychotic symptom severity or distress. Conclusion Several limitations of the existing studies limit the conclusions that can be drawn from the existing evidence regarding the link between childhood adversity and cognitive ability, and future research in prodromal samples is essential. The empirical study showed that there is a link between childhood adversity and cognitive ability in those at clinical high risk of developing psychosis, before disorder onset, that is not present in controls. This suggests that this may form a vulnerability in those at high risk for psychosis, rather than a more general mechanism present in the typical population.