Brain Structural Abnormalities at the Onset of Schizophrenia and Bipolar Disorder: A Meta-analysis of Controlled Magnetic Resonance Imaging Studies

A number of structural brain imaging studies and meta-analytic reviews have shown that multiple subtle brain abnormalities are consistently found in schizophrenia and bipolar disorder. Several studies suggest that schizophrenia and affective psychoses share a largely common pattern of brain abnormalities. Aim of the present study was to compare, by means of a meta-analytic approach, brain structural abnormalities, as detected by Magnetic Resonance Imaging (MRI), found at the onset of schizophrenia and bipolar disorder in order to address the question of the specificity of brain abnormalities across diagnostic groups. Forty-five studies were identified as suitable for analysis. In both schizophrenic and bipolar patients significant overall effect sizes were demonstrated for intracranial, whole brain, total grey and white matter volume reduction as well as for an increase of lateral ventricular volume at disease onset. Thus, the available literature data strongly indicate that some brain abnormalities are already present in first-episode schizophrenia or bipolar disorder and that there is a significant overlap of brain abnormalities in affective and non-affective psychotic disorders at the onset of the disease. However, whole grey matter volume deficits and lateral ventricular enlargement appear to be more prominent in first-episode schizophrenia whereas white matter volume reduction seems more prominent in bipolar disorder. The common vs specific trajectories of brain pathomorphology in schizophrenia and bipolar disorder are discussed.