Self-compassion, self-referential caudate circuitry, and adolescent suicide ideation.

Suicide is the second leading cause of death in youth, and depression is a strong proximal predictor of adolescent suicide. It is important to identify psychological factors that may protect against suicide ideation in depressed adolescents. Self-compassion may be such a factor. Converging evidence indicates the inverse association between self-compassion and suicide ideation, but the neural mechanisms underlying their link remain unknown. Because self-referential caudate activity is associated with both self-compassion and suicide ideation, its functional connectivity might explain their relationship. In this study, we examined the relationship between self-compassion and caudate functional connectivity during self-appraisals, a typical self-referential paradigm, and their associations with suicide ideation in both depressed and healthy youth. In the scanner, 79 depressed youth and 36 healthy controls evaluated, from various perspectives, whether phrases they heard were self-descriptive. Self-compassion and suicide ideation were rated with self-report and interview-based measures. We found that self-compassion was associated with stronger left caudate functional connectivity with bilateral posterior superior temporal sulcus/temporoparietal junction, the left middle temporal gyrus (MTG), and the left middle occipital gyrus during positive versus negative self-appraisals. Stronger left caudate connectivity with the left MTG explained the association between higher self-compassion and lower suicide ideation, even controlling for non-suicide ideation depression severity, anxiety severity, and non-suicidal self-injurious behavior. The findings suggest that the left caudate to MTG connectivity during positive versus negative self-referential processing could be a biomarker to be targeted by neural stimulation interventions for reducing suicide ideation in depressed youth, combined with self-compassion interventions.