Opposite Effective Connectivity in the Posterior Cingulate and Medial Prefrontal Cortex between First-Episode Schizophrenic Patients with Suicide Risk and Healthy Controls

Huiran Zhang,Zhening Liu,Haojuan Tao,Baoci Shan,Lin Xu,Tumbwene E Mwansisya,Zhimin Xue,Zhong He,Weidan Pu,Xiaomei Wei,Aimin Hu,Allan Siegel

doi:10.1371/journal.pone.0063477

Abstract

ObjectiveThe schizophrenic patients with high suicide risk are characterized by depression, better cognitive function, and prominent positive symptoms. However, the neurobiological basis of suicide attempts in schizophrenia is not clear. The suicide in schizophrenia is implicated in the defects in emotional process and decision-making, which are associated with prefrontal-cingulate circuit. In order to explore the possible neurobiological basis of suicide in schizophrenia, we investigated the correlation of prefrontal-cingulate circuit with suicide risk in schizophrenia via dynamic casual modelling.MethodParticipants were 33 first-episode schizophrenic patients comprising of a high suicide risk group (N = 14) and a low suicide risk group (N = 19). A comparison group of healthy controls (N = 15) were matched for age, gender and education. N-back tasking functional magnetic resonance imaging data was collected.ResultsCompared with healthy controls group, the two patients groups showed decreased task-related suppression during 2-back task state versus baseline state in the left posterior cingulate and medial prefrontal cortex; the hyper-connectivity from the left posterior cingulate cortex to the left medial prefrontal cortex existed in both schizophrenic patients groups, but hypo-connectivity in the opposite direction only existed in the schizophrenic patients group with high suicide risk.ConclusionsThe hyper-connectivity from the left posterior cingulate cortex to the left medial prefrontal cortex may suggest that the abnormal effective connectivity was associated with risk for schizophrenia. The hypo-connectivity in the opposite direction may represent a possible correlate of increased vulnerability to suicide attempt.

Highlights

It is well known that schizophrenia contributes substantially to the global burden of disease and is commonly associated with suicide [1]
Compared with healthy controls group, the two patients groups showed decreased task-related suppression during 2-back task state versus baseline state in the left posterior cingulate and medial prefrontal cortex; the hyper-connectivity from the left posterior cingulate cortex to the left medial prefrontal cortex existed in both schizophrenic patients groups, but hypo-connectivity in the opposite direction only existed in the schizophrenic patients group with high suicide risk
The hyper-connectivity from the left posterior cingulate cortex to the left medial prefrontal cortex may suggest that the abnormal effective connectivity was associated with risk for schizophrenia

Summary

Introduction

It is well known that schizophrenia contributes substantially to the global burden of disease and is commonly associated with suicide [1]. Dutta et al reported that suicide in first episode psychosis occurs approximately 12 times more than the general population [2]. The rate of suicidal attempts can be almost up to 40% higher [3]. Some studies suggested that the schizophrenia patients with high suicide risk are characterized by depression, better cognitive function, prominent positive symptoms and low negative symptoms [4,5,6,7]. The neurobiological basis of suicide attempts in schizophrenia is not clear. The previous studies considered that suicidal behavior was associated with dysfunction of decision-making, problem solving and emotional process [8]

Methods

Results

Conclusion