(PS13-96) Examining Treatment Fidelity in Prolonged Exposure and Cognitive Processing Therapy for PTSD Among VA Patients with and Without Co-occurring Substance Use Disorder

Previous research has found evidence that increased treatment fidelity and patient adherence have a positive impact on treatment outcomes for posttraumatic stress disorder (PTSD). It has also been found that comorbidity of substance use disorders (SUD) and PTSD is common in the Veteran population, and that Veterans with comorbid PTSD and SUD receive low rates of evidence-based PTSD treatment. However, the impact of a comorbid SUD on treatment fidelity and patient nonadherence for Veterans undergoing Prolonged Exposure (PE) therapy or Cognitive Processing Therapy (CPT) has not been thoroughly examined. We present results from a national sample of Veterans (n = 64,110) with PTSD who sought PE or CPT treatment in the Veterans Healthcare Administration (VHA) during fiscal years 2017-2019. We compared rates of PTSD treatment non-adherence and inclusion of core therapy elements (indicating treatment fidelity) between Veterans with PTSD+SUD vs. PTSD alone. Specifically, we assessed percentage of sessions in PE and CPT that are missing a core component, frequency of patient nonadherence (e.g., homework completion), and the percentage of individuals who had imaginal exposure provided during the 4^th session or later of PE (indicating good fidelity). Our results indicate that the PTSD+SUD group had slightly greater proportion of core elements included in the session, however this difference was not significant (Z = 1.27, p = 0.20).  The proportion of individuals who received imaginal exposures in the 4^th session or later of PE (indicating better fidelity) was also slightly higher in the PTSD+SUD group (Χ² = 4.65, p = 0.03). Patient nonadherence is slightly higher the PTSD-only cohort having slightly higher non-adherence (Z = -2.54, p</em> = 0.01). Overall, while across cohorts the results were fairly similar, the amount of sessions missing a core component, the frequency of patient nonadherence, and the individuals who did not have imaginal exposures provided during the 4th or PE or later were elevated in the PTSD only group. This indicates that PE and CPT can be delivered with fidelity to individuals with PTSD+SUD and should be regularly offered to this population. In fact, individuals with this comorbidity may do slightly better with regard to fidelity and adherence than individuals without this comorbidity. Further theoretical and clinical implications will be discussed.