Serial Self-Injury in Prison: Institutional Concentration, Chronic Self-Harm Burden, and Implications for...

Self-injurious behavior (SIB) is a low base-rate but high-impact problem in prisons. This study used 10,758 SIB events involving 4,829 individuals over 5 fiscal years in 67 prisons in a large southeastern U.S. system. The unit of analysis was the SIB event, aggregated to prison-years. For each institution, we calculated SIB event and person rates per 1,000 inmates and an event-to-person "seriality" ratio. In FY 2023-2024, 2,306 SIB events involved 1,362 people (26.5 events and 15.7 SIB-engaged inmates per 1,000). The top 20 institutions (30% of prisons) accounted for 68.2% of all SIB events and 69.5% of all SIB-engaged individuals. Event-to-person ratios averaged 1.3 (range = 1.0-2.9); a small group of prisons showed both high rates and high seriality, indicating local clusters of chronic self-injurers, while others had high rates but low seriality or low volume overall. Findings indicate a dual concentration of SIB in specific people and places. We argue that high-volume but low-seriality prisons require broad preventive and environmental strategies, whereas high-seriality "repeat-driven" sites need targeted chronic-care pathways and intensive case management for a small cohort of prisoners. Simple concentration and seriality metrics can help correctional systems prioritize facilities for enhanced mental health staffing, specialized SIB interventions, and sentinel-event review.