Brain volume in first-episode schizophrenia - Systematic review and meta-analysis of magnetic resonance imaging studies

Background Studies of people with schizophrenia assessed using magnetic resonance imaging (MRI) usually include patients with first-episode and chronic disease, yet brain abnormalities may be limited to those with chronic schizophrenia. Aims To determine whether patients with a first episode of schizophrenia have characteristic brain abnormalities. Method Systematic review and meta-analysis of 66 papers comparing brain volume in patients with a first psychotic episode with volume in healthy controls. Results A total of 52 cross-sectional studies included 1424 patients with a first psychotic episode; 16 longitudinal studies included 465 such patients. Meta-analysis suggests that whole brain and hippocampal volume are reduced (both P < 0.0001) and that ventricular volume is increased (P < 0.0001) in these patients relative to healthy controls. Conclusions Average volumetric changes are close to the limit of detection by MRI methods. It remains to be determined whether schizophrenia is a neurodegenerative process that begins at about the time of symptom onset, or whether it is better characterised as a neurodevelopmental process that produces abnormal brain volumes at an early age.