Evidence for progressive brain abnormalities in early schizophrenia: a cross-sectional structural and functional connectivity study

It has long been debated whether a progressive process is involved in schizophrenia. The aim of the current study was to determine whether a progressive process was involved in patients with early schizophrenia, who were drug naive or had received short-term minimal antipsychotic treatment to avoid the distortion through medication effects. Twenty-eight patients with schizophrenia with illness-duration of up to 3 years and twenty-six matched healthy controls were recruited. Structural and functional brain networks were examined based on diffusion tensor imaging (DTI) and functional magnetic resonance imaging (fMRI). The intergroup differences and correlation with illness duration in the patient group were surveyed. The schizophrenic patients showed lower fractional anisotropy (FA) values in the corpus callosum and corona radiata. Negative correlations of illness duration with FA values were observed in similar regions. During functional analysis, reduced functional connectivity between bilateral temporoparietal-junction (TPJ) and the posterior cingulate cortex (PCC) were found in the default mode network (DMN) in schizophrenic patients. In addition, the left TPJ showed gradually weaker functional connectivity with PCC and the medial prefrontal cortex (MPFC) in DMN as the duration of schizophrenia increased. The results suggested that early in the disease process patients have decreased connectivity in both structural and functional networks and that the weaker structural and functional connectivity negatively correlated with illness duration, which provided evidence for progressive brain abnormalities in early schizophrenia.