Cumulative Lead Exposure in Veterans with PTSD: Examining Firearm Use and Cognitive Therapy Outcomes with novel portable X-Ray Fluorescence - PROJECT SUMMARY Veterans are at significantly high risk for post-traumatic stress disorder (PTSD), depression, and suicide by firearm; all three are linked to lead exposure. Preliminary evidence from our team identified firearms as a significant source of lead exposure in civilians, likely through take-home dust from lead-based primers and ammunition. Disconcertingly, the mental and physical impact of lead exposure remains poorly understood due to a focus on acute (blood) rather than cumulative (bone) measures and despite the passage of the 2022 PACT Act encouraging research on Veterans Exposures. When considering cases of PTSD, depression, and suicidal ideation, one of the most successful treatments is Cognitive Processing Therapy. Cognitive Processing Therapy is rooted in cognitive behavioral theory; as such, individuals with diminished cognitive abilities and heightened anger experience worse treatment outcomes. Thus, the well-established effects of lead on lower cognitive abilities and elevated hostility may limit the efficacy of Cognitive Processing Therapy. To address the gaps in the literature and enhance the health of Veterans and active duty servicemembers, there is a vital need to: 1) understand how specific sources of lead exposure (e.g., firearm use) impacts overall lead levels within this vulnerable population; and 2) understand the impact cumulative lead exposure has on Cognitive Processing Therapy outcomes. To fill these critical gaps, we plan to leverage an ongoing study of 350 Veterans and active military servicemembers who provided comprehensive self-report measures of psychopathology, clinician interviews, firearm and lead exposure, and novel noninvasive in vivo 3-minute bone scans for cumulative lead exposure via portable x-ray fluorescence (pXRF). Next, we will examine the association of all-cause tibia lead levels with clinical outcomes (pre-and post-treatment, 3-,6-, and 12-months after treatment). This study will be the first to characterize firearm-related sources of cumulative lead exposure and all-cause leads effect on psychosocial treatment outcomes in Veterans and active duty servicemembers. The findings could improve mental health outcomes through actionable insights for participants and providers, eventually informing and enhancing psychosocial treatment options, of which there are none for adult lead exposure. This Ruth L. Kirschstein National Research Service Award (NRSA) Individual Predoctoral Fellowship (Parent F1) application aligns with my goals of becoming an independent and interdisciplinary researcher through the provision of valuable mentoring, protected research time, and coursework outside my graduate programming.