A REVIEW OF CAUDATE NUCLEUS VOLUME IN FIRST EPISODE PSYCHOSIS

Object: The object of this review was to identify and critically review studies that investigated caudate volume in first episode psychosis patients, with a further interest into the possible effects of antipsychotic medication. Method: We searched the Medlin and Pubmcd databases using the medical subject heading (MESH) terms: 'schizophrenia' and 'caudate volume' and 'MRI". The electronic search was then repeated using the terms 'psychosis' and 'caudate volume'. Studies published up to the 31" December 2007 as an article, rather than a letter or abstract, were included. Results: A total of U cross sectional studies and 6 longitudinal studies included patients with a first psychotic episode in comparison to healthy controls. These studies suggest that at the time of the first psychotic episode, before treatment is started, patients have a smaller caudate volume than healthy individuals; once treatment has begun, the caudate becomes similar in volume in first episode psychosis patients and in healthy controls. Longitudinal studies suggest that treatment with antipsychotic drugs, particularly typical antipsychotics, may cause an increase in caudate volume over time. Conclusions: Differences in findings on caudate N olume in first episode psychosis may be explained by both the pathophysiology of psychosis and the use of antipsychotic medications. To further understand the role of these changes, studies would benefit from evaluating larger samples of antipsychotic na ve individuals at illness onset.