Characteristics of the corpus callosum in chronic schizophrenia treated with clozapine or risperidone and those never-treated

Background: The corpus callosum (CC) deficits have been well documented in chronic schizophrenia. However, the long-term impacts of antipsychotic monotherapies on callosal morphology remain unclear. This cross-sectional study sought to explore micro- and macrostructural characteristics of the CC in never-treated patients and those with long-term mono-antipsychotic treatment. Methods The study included twenty-three clozapine-treated schizophrenia patients (CT-SCZ), 19 risperidone-treated schizophrenia patients (RT-SCZ), 23 never-treated schizophrenia patients (NT-SCZ), and 35 healthy controls (HCs). High resolution structural images and diffusion tensor imaging (DTI) data for each participant were obtained via a 3.0 T MR scanner. FreeSurfer was used to examine the volumes and fractional anisotropy (FA) values of the CC for each participant. Results There were significant deficits in the total and subregional CC volume, and white matter integrity in NT-SCZ in comparison with healthy subjects. Compared with NT-SCZ, both CT-SCZ and RT-SCZ showed significantly increased FA values in the anterior CC region, while only RT-SCZ showed significantly increased volume in the mid-anterior CC region. Moreover, the volume of the mid-anterior CC region was significantly smaller in CT-SCZ compared to HCs. No correlations of clinical symptoms with callosal metrics were observed. Conclusions Our findings provide insight into micro- and macrostructural characteristics of the CC in chronic schizophrenia patients with or without antipsychotic medications. These results suggest that chronic exposure to antipsychotic medications may have an impact on brain structure of schizophrenia patients, especially in those with risperidone treatment.