Abstract
Nonsuicidal self-injury (NSSI), intentionally inflicting harm to one's body without suicidal intent, is a significant mental health problem in adolescents. Biological mechanisms underlying NSSI are still not well understood but there is some support for altered pain sensitivity. Here we explored the processing of affective touch, an interoceptive modality which has not been explored previously in NSSI. Using functional magnetic resonance imaging, we examined how adolescents with NSSI (N = 27), compared to controls (N = 26), responded to stroking touch. In the scanner, participants rated the pleasantness and intensity of slow and fast stroking touch on their forearm. A small-volume correction analysis focusing on bilateral insula was performed in addition to a whole-brain analysis. For both approaches and for behavioral ratings, 2×2 factorial ANOVAs were performed. Social touch was also assessed via the Social Touch Questionnaire. Compared to controls, the NSSI group had lower pleasantness ratings, for both slow and fast stroking touch, and higher activity during touch in the insular cortex, a key structure in interoceptive processing. In addition, adolescents with NSSI self-reported avoidance toward social touch. Results suggest that this transdiagnostic clinical sample of adolescent females with NSSI exhibits avoidance to social touch, lower hedonic appreciation of dynamic, innocuous touch, and heightened insular activity in response to touch, potentially linked to altered interoceptive processing.