The EEG-Indexed Auditory Mismatch Negativity as a Biomarker to Predict Psychosis Onset

Schizophrenia is a disorder that is often preceded by early symptoms of psychosis, however the accuracy of predicting conversion based on clinical symptoms is low. The healthy human brain is able to detect changes in our auditory environment, whether we are paying attention or not and even while we are sleeping. This function, originally thought to have developed so we could detect sounds indicating danger approaching, may seem simple but is an important part of our daily lives and is the result of complex computations within the brain. It has been long reported that schizophrenia patients show deficiencies in this auditory change detection mechanism, and that this might be an observable marker of greater dysfunction within the brain of those affected. Recent work has suggested that this deficit may be present in individuals at risk of developing a disorder of psychosis, such as schizophrenia, before psychosis emerges. What is unclear, however, is whether early-occurring deficits in auditory change detection can predict who will transition to psychosis and who will not. If we were able to identify an objective, accurate biological marker of psychosis risk, this would allow clinicians to initiate early treatment in those who will transition to psychosis, while avoiding unnecessary treatments in those who will not. This project aims to shine a light on this question by examining auditory change detection in individuals at risk of developing a psychotic disorder, whether it be due to a family history of schizophrenia or the presence of early symptoms that may or may not turn into psychosis. It is hoped that we might identify that elusive objective biological marker that would allow for accurate prediction of psychosis risk and early treatment, so as to change the course of this illness that the World Health Organization has called schizophrenia "youth's greatest disabler due to its typical emergence during young adulthood and the devastating impact on functioning".