Developmental and Momentary Dynamics in the Onset and Maintenance of Nonsuicidal Self-Injurious Behavior and Borderline Personality Disorder

Purpose of Review Traditional conceptualizations of both nonsuicidal self-injury (NSSI) and borderline personality disorder (BPD) typically rely on static and unidirectional, linear associations between key biopsychosocial vulnerabilities. Instead, we argue that utilizing a complex dynamic systems view of NSSI and BPD will advance the field, as such conceptual models allow for analysis of bottom-up effects for key vulnerabilities on disorder and behavior emergence, as well as top-down effects of the emergent disorder on underlying vulnerabilities. Recent Findings Following the presentation of a novel framework highlighting momentary and developmental dynamics, we explore several advances in the field that exhibit key dynamic qualities or inform dynamic conceptualizations of NSSI and BPD. At the momentary dynamic level, several advances are being made with multimethod and repeated assessment approaches, as well as advanced bidirectional and complex modeling procedures. Additional progress is being made at the developmental dynamic level, although several questions have arisen regarding the problem of onset and subsequent trajectory, particularly with issues such as pain perception and the interplay between interpersonal, emotional, and behavioral symptoms before and after treatment. Summary Self-injury and BPD both exhibit substantial momentary and developmental dynamics in underlying vulnerabilities, including potential variance in momentary dynamics as a function of psychopathological developmental stage (e.g., onset versus maintenance versus recovery). Recent work has highlighted the necessity of utilizing multimodal research to encapsulate a holistic view of the interplay of several vulnerability factors, the developmental importance of assessment timing, and the need to examine the dynamic interplay between affect, behavior, and interpersonal experiences in BPD and/or NSSI. Research also indicated substantial variation in key vulnerability factors at both between- and within-person levels, highlighting the utility of harnessing statistical models that allow for the simultaneous incorporation of numerous variables at both levels and across several time points. As such, by using a complex dynamic systems conceptualization, we can begin to better understand integrated connections between key vulnerabilities, how they collectively interact in the short term, and how changes in the dynamic interplay between vulnerabilities may arise over the long term and with successful treatment.