4 - (SYM 25) Reducing HIV Risk Among Rural Native Americans: A Parallel Effectiveness Study of PTSD and Substance Use Treatments

Addressing the dual challenges of trauma and substance use is critical in reducing HIV risk, particularly in underserved populations. Prior research has found that culturally adapted Cognitive Processing Therapy successfully reduced PTSD and substance use among rural Native Americans but did not reduce HIV risk behavior (Pearson et al., 2019). This study aimed to test targeted PTSD or substance use treatments as potential pathways for reducing HIV risk via a parallel effectiveness trial. Participants were from a Pacific Northwest tribal community (N=125). Inclusion criteria included age 16+, current sexual activity, probable PTSD, and substance use disorder. Eligible individuals were randomized to Narrative Exposure Therapy (NET) or Motivational Interviewing with cognitive-behavioral therapy skills training (MIST). Interventions were culturally tailored, incorporating cultural ceremony and values, and were delivered by local community counselors in six 90–120-minute sessions. Both NET and MIST significantly reduced PTSD symptoms, high-risk sexual behavior, and substance use from baseline to 6-month follow-up. There was greater improvement in NET (vs. MIST) on high-risk sexual behavior (unprotected sex and sex while intoxicated) and substance use (alcohol and drug use), with effect sizes ranging from small to large (d=0.28–1.25). Univariate growth curve models of PTSD symptoms and substance use cravings indicated that changes in both PTSD symptoms and substance use cravings were significant from the first to the final session of treatment, which was unrelated to treatment condition. We examined the association between changes in PTSD symptoms and changes in substance use cravings via a parallel process growth curve model. Results indicated that there was a strong positive correlation (r = .87, p < .001) between changes in PTSD symptoms and changes in substance use cravings between the first and final session, which was unrelated to treatment condition. Participants with the largest PTSD reductions also experienced the largest reductions in substance use cravings. Findings suggest targeting PTSD or substance use disorder are both viable pathways for reducing HIV risk among rural Native Americans, but addressing PTSD may have added benefits. Implementation of culturally adapted trauma-focused strategies may address interconnected health disparities in vulnerable populations.