Grant: Operating Grant

People with schizophrenia experience symptoms such as hallucinations and delusions. It is a devastating illness for those affected, estimated at more than 240,000 Canadians, and their families (Goeree et al 2004). A natural chemical present in the brain called dopamine carries signals between nerve cells and plays an important role in schizophrenia. People who have the disease, or those at very high risk of developing it, become worse when they are in stressful situations. Repeated exposure to stressors may change the amount of dopamine released in the brain and could explain why the disease develops in vulnerable individuals, and why those who have the illness relapse. It is possible to detect brain levels of dopamine in humans by using a radioactive dye and a positron emission tomography (PET) camera. In this study, PET will be used to measure brain levels of dopamine in the cerebral cortex during a stressful task in healthy volunteers, individuals at very high risk of developing schizophrenia, and patients. Information on changes in dopamine release in the brain, hormonal changes and psychological characteristics will be collected, and the interactions between them explored. This is anticipated to provide the knowledge needed to detect the disease at an earlier stage and for identification of socio-psychological risk factors that will help target mental health interventions.