Cingulate cortex cortical thickness associated with non-suicidal self-injury and suicide risk in youth with mood disorders

Background: Non-suicidal self-injury (NSSI) is associated with increased suicide risk and is prevalent among patients with mood disorders, including major depressive disorder (MDD) and bipolar disorder (BD). Structural alterations in cortical regions involved in emotional processing are linked to NSSI as well as suicide risk in mood disorders. Few studies have investigated the neurobiological substrates of NSSI and suicidal thoughts and behaviors (STB), particularly comparing youth with BD to those with MDD. There is a critical need to examine NSSI and STB in the context of MDD and BD separately, as risks differ between these populations. Methods: This study investigated the relationship between anterior cingulate cortex (ACC) cortical thickness and volume and NSSI and STB in youth with mood disorders. One-hundred thirty-seven youth (86 with MDD and 51 with BD), ages 13 to 21, completed a diagnostic interview, clinical assessments, and 3 T magnetic resonance imaging. Morphometric analysis of brain images was performed to evaluate differences in cingulate regions of interest. Results: Seventy-five youth reported a NSSI. Youth with BD were more likely to report NSSI than youth with MDD. In addition, youth with BD and NSSI were more likely to have a suicide attempt and had significantly lower cortical thickness in the right caudal ACC (p = .009, eta 2 = 0.050) compared to youth with MDD and NSSI. Conclusions: These structural alterations in the ACC, which impact emotional regulation and pain processing, may be linked to the increased NSSI and suicide risk observed in BD.