Structural and Functional Abnormalities in the Caudate Nucleus of Schizophrenic Patients with and without Obsessive Symptoms

Background: Obsessive–compulsive symptoms (OCS) have been frequently described in schizophrenic populations. There is a controversy on whether this co-occurrence is more than just comorbidity or represents a distinct subgroup in schizophrenia. Aim: The aim of this study was to investigate whether there are possible underlying structural and functional differences between schizophrenic patients with and those without OCS. Patients and methods: Participants in this study were divided into three groups: 20 patients having schizophrenia with OCS; 20 patients having schizophrenia without OCS (both were diagnosed according to DSM-IV-TR); and 20 matching controls. All participants underwent an MRI for volumetric measurement of the caudate nucleus and a magnetic resonance spectroscopy to measure choline (Cho), creatine, and N-acetyl aspartate (NAA) in the caudate nucleus. Results: Caudate volume was found to be reduced in schizophrenic patients with or without OCS (P≤0.05). Magnetic resonance spectroscopy findings showed that schizophrenic patients without OCS had significant increase in Cho concentration (P≤0.05), but average NAA concentration. In contrast, schizophrenic patients with OCS had significant reduction in NAA concentration (P≤0.05) with average Cho concentration. Conclusion: Schizophrenic patients with OCS may have an atypical set of neuroradiological characteristics that would specifically categorize it within the schizophrenia spectrum.