Click here to read a Haitian Creole translation of this web page (by Web Geek Science)!

Schizophrenia is a brain disorder characterized by delusions, hallucinations, disturbances in thinking and withdrawal from social activity.  It affects about one in 100 Canadians and their families.

The Neuropsychiatry group at the University of Western Ontario (http://www.psychiatry.med.uwo.ca/neuropsychi.asp?id=3), led by Dr. Williamson, was one of the first groups to apply MRS to the study of brain chemistry in neuropsychiatric disorders.  The finding of increased glutamatergic metabolites in untreated schizophrenic patients has now been replicated by a number of centres across the world. Another recent finding, progressive loss of glutamatergic metabolites and gray matter in the early years of illness was reported by the group in the British Journal of Psychiatry. The paper showed that there is a structural and chemical basis for the psychological deterioration in this illness which was first called ‘dementia praecox’ when it was described about a century ago.

Recently a new brain imaging technique was developed to look at functional brain circuits. The approach is based on low frequency fluctuations in the same BOLD signal which is used for standard functional imaging during tasks. However, this technique allows us to look at the resting or ‘default’ network which is associated with self-reflection. Dr. Williamson edited a theme issue in Schizophrenia Bulletin reporting the first evidence that the default network is abnormal in schizophrenic patients. The figure shows brain regions that were activated with hallucinations in schizophrenic patients. The area in orange/yellow is the auditory cortex. The activity in this region correlated with parts of the default network so the patients were aware of the thoughts but there was no correlation with the anterior part of the default network associated with the sense that the thoughts were produced by the patients. Consequently, they were experienced as hallucinations. Several similar studies are now underway in bipolar and posttraumatic stress disorder patients. Preliminary work suggests that these networks may distinguish different disorders well enough to be used in diagnosis.