In the United States, youth have the highest burden of nonfatal self-inflicted injury (ie, deliberate physical harm against oneself, inclusive of suicidal and nonsuicidal intent) requiring medical attention. 1 One study found that emergency department (ED) visits for these injuries during the 1993 to 2008 period varied by age group, ranging from 1.1 to 9.6 per 1000 ED visits, with adolescents aged 15 to 19 years exhibiting the highest rates. 1 Selfinflicted injury is one of the strongest risk factors for suicide-the second-leading cause of death among those aged 10 to 24 years during 2015. 2 This study examined trends in nonfatal self-inflicted injuries treated in hospital EDs among US children, adolescents, and young adults aged 10 to 24 years (hereafter referred to as youth). MethodsThe National Electronic Injury Surveillance System-All Injury Program (NEISS-AIP) collects data on all first-time visits for nonfatal injuries treated in 66 US hospital EDs through stratified probability sampling, allowing for the derivation of national estimates. 3

Bullying is often ongoing during middle- and high-school. However, limited research has examined how cumulative experiences of victimization, perpetration, and bystander behavior impact adolescent behavioral and mental health and academic achievement outcomes at the end of high school. The current study used a sample of over 8000 middle- and high-school students (51% female; mean age 12.5 years) from the Rural Adaptation Project in North Carolina to investigate how cumulative experiences as a bullying victim and perpetrator over 5 years, and cumulative experiences of bystander behavior over 2 years impacted students' aggression, internalizing symptoms, academic achievement, self-esteem, and future optimism. Following multiple imputation, analysis included a Structural Equation Model with excellent model fit. Findings indicate that cumulative bullying victimization was positively associated with aggression and internalizing symptoms, and negatively associated with self-esteem and future optimism. Cumulative bullying perpetration was positively associated with aggression and negatively associated with future optimism. Cumulative negative bystander behavior was positively associated with aggression and internalizing symptoms and negatively associated with academic achievement and future optimism. Cumulative prosocial bystander behavior was positively associated with internalizing symptoms, academic achievement, self-esteem, and future optimism. This integrative model brings together bullying dynamics to provide a comprehensive picture of implications for adolescent behavioral and mental health and academic achievement.

Firearm homicide is the leading cause of violence-related youth mortality. To inform prevention efforts, we analyzed event-level data to identify unique precursors to firearm conflicts. Youth (ages:14–24) seeking Emergency Department (ED) treatment for assault or for other reasons and reporting past 6-month drug use were enrolled in a 2-year longitudinal study. Time-line follow-back substance use/aggression modules were administered at baseline and each 6-month follow-up. Violent non-partner conflicts were combined across time-points. Regression analyzed: a)antecedents of firearm-related conflicts (i.e., threats/use) as compared to non-firearm conflicts; and b)substance use on conflict (vs. non-conflict) days for those engaged in firearm conflict. During the 24-months, we found that 421-youth reported involvement in violent non-partner conflict (n=829-conflicts;197-firearm/632-non-firearm). Among firearm conflicts, 24.9% involved aggression and 92.9% involved victimization. Retaliation was the most common motivation for firearm-aggression (51.0%), while “shot for no reason” (29.5%) and conflicts motivated by arguments over “personal belongings” (24.0%) were most common for firearm-victimization. Male sex (AOR=5.14), Black race (AOR=2.75), a ED visit for assault (AOR=3.46), marijuana use before the conflict (AOR=2.02), and conflicts motivated by retaliation (AOR=4.57) or personal belongings (AOR=2.28) increased the odds that a conflict involved firearms. Alcohol (AOR=2.80), marijuana (AOR=1.63), and prescription drugs (AOR=4.06) had a higher association with conflict (vs. non-conflict) days among youth reporting firearm conflict. Overall, we found that firearm conflicts are differentially associated with substance use and violence motivations. Addressing substance use, interrupting the cycle of retaliatory violence, and developing conflict resolution strategies that address escalation over infringement on personal belongings may aid in decreasing and preventing adolescent firearm violence.