Meta-analysis of regional brain volumes in schizophrenia

Objective: The authors' goal was to determine whether patients with schizop hrenia differ from comparison subjects in regional brain volumes and whethe r these differences are similar in male and female subjects. Method: They c onducted a systematic search for structural magnetic resonance imaging (MRI ) studies of patients with schizophrenia that reported volume measurements of selected cortical, subcortical, and ventricular regions in relation to c omparison groups. They carried out a meta-analysis of the volumes of these regions in the patients with schizophrenia and the comparison subjects usin g a random effects model; they also used random effects regression analysis to examine the influence of gender on effect sizes. Results: Fifty-eight s tudies were identified as suitable for analysis; these studies included 1,5 88 independent patients with schizophrenia. Assuming a volume of 100% in th e comparison group, they found that the mean cerebral volume of the subject s with schizophrenia was smaller (98%), but the mean total ventricular volu me of the subjects with schizophrenia was greater (126%). Relative to the c erebral volume differences, the regional volumes of the subjects with schiz ophrenia were 94% in the left and right amygdala, 94% in the left and 95% i n the right hippocampus/amygdala, and 93% in the left and 95% in the right parahippocampus. Relative to the global ventricular system differences, the largest differences in ventricular subdivisions were in the right and left body of the lateral ventricle, where the volumes of schizophrenic subjects were 116% and 116%, respectively. For most regions, effect size was not si gnificantly related to gender, Conclusions: Regional structural differences in patients with schizophrenia include bilaterally reduced volume of media l temporal lobe structures. There is a need for greater integration of resu lts from structural MRI studies to avoid redundant research activity.