Biological and environmental risk factors for developing psychotic mental illness

Childhood trauma is a well-established risk factor for developing psychosis, with known effects on the developing brain. Associate Professor Melissa Green and colleagues investigated the associations between childhood trauma exposure and social cognitive processes, as well as facets of ‘schizotypy’ in people with schizophrenia and bipolar disorder. Schizotypy refers to a set of cognitive and behavioural characteristics that represent risk for schizophrenia in the general population. We showed that adults reporting a history of childhood trauma had higher levels of schizotypy, especially suspiciousness, relative to those who were not exposed to trauma, regardless of whether they had a psychiatric diagnosis (Quidé, Cohen-Woods, O’Reilly, Carr, Elzinga, & Green, 2018). Trauma-exposed individuals also showed more significant problems with social cognition, lending some support to the idea that early life trauma-exposure may impact the development of brain functions, potentially increasing vulnerability for psychosis via social cognitive disturbances that give rise to paranoia and suspiciousness. However, the mechanisms by which these processes impact brain function remain to be understood. One proposal is that early life trauma-exposure sets off a cascade of biological processes related to immune function, with long-term impacts on brain development. We found that trauma-exposed cases with schizophrenia show higher levels of pro-inflammatory cytokines, relative to non-exposed cases. These results are being followed up to determine the epigenetic markers of trauma-exposure, and their relation to heightened inflammatory responses and aberrant brain function in people with schizophrenia and bipolar disorder.