(PS4-87) Evaluating the Effectiveness of Cognitive Processing Therapy (CPT) with the Stellate Ganglion Block (SGB): Findings from an Open-Label Randomized Wait-List Clinical Trial

Abstract Text: Posttraumatic stress disorder (PTSD) is a widespread mental health challenge among U.S. military personnel. Cognitive processing therapy (CPT) for PTSD has proven to be effective in reducing PTSD symptoms; however, some patients continue to experience elevated PTSD symptoms, especially hyperarousal symptoms, after completing CPT. Previous research indicates that the stellate ganglion block (SGB) significantly reduces PTSD symptoms, primarily focusing on hyperarousal. Integrating CPT and SGB could therefore augment treatment outcomes among patients diagnosed with PTSD. However, the effectiveness of this approach has not yet been investigated. Participants were 86 US military personnel and veterans (M_age=42, SD=10) who mostly identified as non-Hispanic (87%), White (86%), and male (73%). The participants received massed sessions of CPT in a condensed timeframe and were randomly assigned to receive the SGB procedure either during the first week or 3 months after CPT. Participants completed the PTSD Checklist for DSM-5 (PCL-5) multiple times during the one-year study period. Data collection will be complete in May of 2025, but results from the first 4 months of follow-up are reported here. The analyses will be updated at that time and presented on. Mean baseline PCL-5 scores were 50.2±17.0 in the SGB during CPT group and 50.0±15.9 in the SGB post-CPT group. Changes in PCL-5 scores significantly differed between conditions (F(9,497)=4.3, p< .001), with larger reductions observed in the SGB during CPT group than the SGB post-CPT group at week 4 (19.0±16.7 vs. 31.7±16.7; d=-0.77) and week 8 (20.2±13.8 vs. 34.5±17.9; d=-0.89). PCL-5 scores further decreased in the wait-list group after receiving the SGB during week 12, “catching up” to the SGB during CPT group by week 16 (21.1±18.9 vs. 22.6±16.6; d=-0.09). Our findings suggest integrating SGB with CPT simultaneously is associated with quicker and more pronounced reductions in PTSD symptoms than receiving SGB after CPT. Investigating the relationship between CPT and SGB allows providers to bridge the gap between addressing the physical and mental symptoms of PTSD. Limitations of the study include the lack of a sham injection or treatment arm excluding SGB.