Studies utilising structural neuroimaging methodo- logies have been used extensively over the past 25 years to investigate the underlying neurobiology of schizophrenia. From the initial reports of ven- tricular enlargement using computed tomography (CT), to the more recent high-resolution magnetic resonance imaging (MRI) examinations of smaller brain regions, a consensus has emerged of consistent, albeit subtle, changes in a variety of brain regions [1,2]. These include reduced medial temporal lobe volumes, including the hippocampus and amygdala. While these studies have been important in providing conclusive evidence for neuroanatomical differences in the brains of people meeting the diagnostic criteria for schizophrenia, the implications of these findings for understanding the development of psychosis in young people have been less clear. There is a general consensus that many variables derived from structural brain imaging differ signifi- cantly in patients who have recently been diagnosed with DSM-IV schizophrenia and healthy volunteers [3,4], indicating that neuroanatomical abnormalities are present from the onset of the disorder. Some studies have also suggested that there may be progres- sive changes that occur over time, although to date there have been few studies conducted over a time interval of longer than 5 years where state-of-the-art MRI techniques have been used [5,6]. Evidence is Structural brain imaging and the prevention of schizophrenia: can we identify neuroanatomical markers for young people at risk for the development of schizophrenia? Philip B. Ward Objective: To examine the potential role of measures derived from structural brain imaging as phenotypic markers for the development of schizophrenia. Method: Literature review of results of MRI-based assessments of brain structure in patients with schizophrenia, their first-degree relatives and factors that affect interpretation of such results. Results: Reliable differences in brain structure can be detected in patients with schizophrenia, including those experiencing a first episode of psychosis. Further research is required to determine whether these differences are progressive, how they relate to potential confounding factors such as comorbid substance abuse and the functional consequences of the relatively subtle changes observed. Conclusions: Further research is needed before structural brain change can be considered as a phenotypic marker for those at risk of developing schizophrenia. Large-scale collaborative research in clinical and normal volunteer groups using standardised assessment protocols would enable the early identification of those findings with predictive power in at-risk populations. Key words: first-episode psychosis, magnetic resonance imaging, schizophrenia. Australian and New Zealand Journal of Psychiatry 2000; 34 (Suppl.):S127–S130 Philip B. Ward, Associate Professor School of Psychiatry, University of New South Wales, Sydney, Australia. Address for correspondence: Schizophrenia Research Unit, Don Everett Building, Liverpool Hospital, Liverpool BC, New South Wales 1871, Australia. Email: p.ward@unsw.edu.au Aust NZ J Psychiatry Downloaded from informahealthcare.com by 112.124.59.107 on 05/20/14 For personal use only.