White matter and impulsivity are prospectively associated with non‑suicidal self‑injury in youth: evidence for sex differences

Non-suicidal self-injury (NSSI) typically begins in adolescence and is associated with higher impulsivity and compromised white matter microstructure in the brain. Identifying early predictors of NSSI is a high priority. We used data from the Adolescent Brain Cognitive Development Study to examine whether baseline white matter, specifically generalized fractional anisotropy (GFA), and different facets of impulsivity were prospectively associated with NSSI onset two years later (Y 2 ). We also examined interactions with sex. We identified 209 youth aged 8–11 years who reported NSSI at Y 2 , but not at baseline (incident NSSI; iNSSI) and 209 controls matched by demographic and clinical characteristics. We conducted a Least Absolute Shrinkage and Selection Operator (LASSO) regularization, which yielded an AUC of .60, to narrow down predictors for logistic regression. Significant main effects indicated that lower GFA of the left parolfactory section of the cingulum (OR = 0.63) and higher negative urgency (OR = 1.54) were prospectively associated with Y 2 NSSI. Sex interactions indicated that the relations between Y 2 NSSI and lower GFA of the left parolfactory section of the cingulum (OR = 1.75) and higher negative urgency (OR = 0.60) were driven by males. Higher sensation seeking (OR = 1.36) and lack of perseverance (OR = 1.46) were more strongly associated with Y 2 NSSI among females than males. Future work is needed to better understand the course of development of white matter microstructure and impulsivity as it relates to NSSI.