Resting-state functional connectivity of the anterior cingulate cortex in young adults depressed patients with and without suicidal behavior

Functional alterations in the subregions of the anterior cingulate cortex (ACC) have been observed in patients with major depressive disorder (MDD). Studies have shown that higher depressive symptoms are associated with altered functional connectivity (FC) in different ACC sub-regions. Suicide is highly prevalent in patients with MDD; however, it is unclear whether suicidal behavior is associated with the FC alterations in the subregions of the ACC in these indibiduals. Seventy-six patients with MDD (41 with and 35 without a history of suicidal behavior) underwent functional magnetic resonance imaging (fMRI) and were assessed using the Hamilton Rating Scale for Depression (HAMD), the Scale for Suicide Ideation (SSI), and the Columbia Scale for Rating of Suicide Severity. We investigated the FC between the ACC subregions and other brain regions in young MDD patients with and without a history of suicidal behavior. The FC in the subregions of the ACC-superior frontal gyrus differed significantly between the two groups. Additionally, the anterior sgACC-right caudate FC and the pgACC-left insula FC were found to be abnormal in the suicidal MDD group. Interestingly, the suicidal ideation score positively correlated with decreased FC in the pgACC-superior frontal gyrus in both groups, but it negatively correlated with increased FC in the anterior sgACC-superior frontal gyrus in the non-suicidal MDD group. Our findings indicate that altered connections of subregions in the ACC may be involved in the neurological mechanisms underlying suicide in young adults with MDD.