Orbitofrontal Lobe Volume Deficits in Antipsychotic-Naïve Schizophrenia: A 3-Tesla MRI Study

Abstract

Background: Prefrontal cortex deficits have been consistently demonstrated in schizophrenia. The orbitofrontal lobe (OFL), a critical component of the prefrontal cortex, subserves social and neuro-cognitive functions. While these functional impairments are established in schizophrenia, the OFL volume deficits have not been well studied, especially in antipsychotic-naïve patients. Aim: To study OFL volume deficits in antipsychotic-naïve schizophrenia patients in comparison with matched healthy controls using high-resolution 3-tesla (3T) magnetic resonance imaging (MRI). Materials and Methods: Fourteen antipsychotic-naïve schizophrenia patients (DSM-IV) and 14 age-, sex-, handedness- and education-matched healthy controls were scanned using 3T MRI. Psychopathology was assessed in the patient group using the scale for assessment of negative symptoms and the scale for assessment of positive symptoms (SAPS). The OFL volume was measured using Region of Interest (ROI)-based manual morphometry technique, with good inter-rater reliability (intra-class correlation coefficient = 0.98). Results: Total OFL volume was significantly smaller in schizophrenia patients (43.3 ± 9.6 mL) in comparison with healthy controls (52.1 ± 12.2 mL) after controlling for the potential confounding effects of age, sex and intracranial volume (F = 5.3, P = .03). Duration of untreated psychosis did not correlate significantly with OFL volumes. There was a trend towards significant negative correlation between the left and total OFL volumes and SAPS scores (r = –0.49, P = .06). Conclusion: OFL volume deficits might underlie the pathogenesis of schizophrenia symptoms with possible neuro-developmental origins.