“…4 Among assault-injured youth seeking urban ED care, almost 25% report having a firearm, with recent violence, attitudes favoring retaliation, and illicit drug use cited as key risk factors for illicit firearm possession. 13 Substance use, which is as high as 55% among assault-injured ED youth, 14 has also been shown to be a key risk factor for a range of high-risk firearm behaviors, including weapon carriage, 15,16 unsafe weapon storage, 16 and firearm-related threats against others. 17 Furthermore, although almost 50% of assaultinjured ED youth have a recent mental health diagnosis (eg, major depressive episode, posttraumatic stress disorder [PTSD]), ,20% have received treatment for that illness, 18 and previous studies have not characterized how a preexisting mental health diagnosis may contribute to future firearm violence risk in this population.…”