Abnormal baseline brain activity in suicidal and non-suicidal patients with major depressive disorder

Previous studies have shown that suicide attempts are strongly associated with major depressive disorder (MDD), and MDD patients who attempt suicide have a high risk of death by suicide throughout their lifetimes. We aimed to explore the differences in resting-state brain activity in MDD patients with and without histories of suicide attempt. We accomplished this using an approach named amplitude of low-frequency fluctuation (ALFF). ALFF reflects the local properties of specific brain regions and provides direct information about impaired regions. This approach differs from functional connectivity. In this study, we compared three groups: MDD patients with and without histories of suicide attempt, and normal controls (NC). The main result is that suicide attempters had increased ALFF in the right superior temporal gyrus (r-STG) relative to both non-suicidal patients (NSU) and NC. In addition, NSU had increased ALFF in the right ventral medial frontal gyrus (r-vMFG) relative to both suicide attempters (SU) and NC. Finally, both NSU and SU had increased ALFF in the left anterior cingulated cortex (l-ACC) and right parahippocampal gyrus (r-PG) and decreased ALFF in the left middle occipital gyrus (l-MOG) and left angular gyrus (l-AG) relative to NC.

► r-STG (right superior temporal gyrus) is found as suicide marker in MDD. ► l-ACC (left anterior cingulated cortex) is found as a marker for MDD in general. ► l-MOG (left middle occipital gyrus) is revealed as a marker for MDD in general. ► Interference in DMN contributes to emotional and cognitive dysregulation in MDD.