Micro‐sequences of anger and shame and non‐suicidal self‐injury in youth: an ecological momentary assessment study

Non-suicidal self-injury (NSSI) is a significant mental health concern with the highest prevalence among adolescents. NSSI has been conceptualized as one of the maladaptive strategies to cope with challenging affect or a form of self-punishment. Although characterizing moment-to-moment associations between shame and NSSI in individuals' real-world environment and partitioning between- and within-person effects is critical for mobile and timely interventions, most studies examined habitual experiences of negative affective states and focused on adults.In this study, we focused on in vivo anger at self and others and shame and NSSI among 158 adolescents 3 weeks following their psychiatric hospitalizations using ecological momentary assessment (EMA) technology.We found that greater between-person levels of anger at self and others were linked to a higher number of subsequent NSSI occurrences within a day. These findings remained primarily unchanged when we statistically adjusted for participants' age, sex assigned at birth, the number of current psychiatric diagnoses, EMA response rates, and youth lifetime history of SI. Within-person increases in NSSI were linked to increased anger at self over and beyond between-person average levels of NSSI.These findings highlight the potential regulatory role of NSSI to decrease negative affective states and point to the clinical utility of assessing and early mobile interventions targeting challenging affect in youth.