Differences in functional connectivity density among subtypes of schizophrenic auditory hallucination.

This study aimed to investigate alterations in brain function among different subtypes of auditory hallucinations (AH) in drug-naïve first episode schizophrenia patients. We recruited 20 patients with drug-naïve first episode schizophrenia who had constant commanding and commenting auditory verbal hallucinations (CCCAVH), 15 drug-naïve first episode schizophrenia patients who had nonverbal auditory hallucinations (NVAH), and 20 healthy controls to participate in this study. We used global functional connectivity density (gFCD) and one-way analysis of covariance to characterize differences in brain function between the two patient groups. Statistical significance was set at P < 0.05. As compared to controls, schizophrenia patients with CCCAVH demonstrated increased gFCD in the right Broca's area, bilateral superior temporal gyri, hippocampus, bilateral insula, and anterior cingulate gyri, and decreased gFCD in the left temporoparietal junction (family-wise error [FEW] correct, P < 0.05). Schizophrenia patients with NVAH demonstrated increased gFCD in the bilateral superior temporal gyri and most of the components of the default mode network (DMN), and decreased gFCD in components of the executive control network (FWE correct, P < 0.05). We found that schizophrenia patients with CCCAVH and NVAH have distinct functional brain patterns. The features observed in patients with CCCAVH are consistent with the "inner speech" hypothesis of AH. Features of patients with NVAH suggest hyperactivity of the superior temporal gyrus and DMN, and hypoactivity of the prefrontal lobe.