(PS4-B34) Clinically Significant Change in Posttraumatic Growth and PTSD Symptoms in a Controlled Trial of Adaptive Disclosure and Cognitive-processing Therapy for Service Members with PTSD

Posttraumatic growth (PTG), posited to be positive psychological change after exposure to high magnitude and traumatic stressors (e.g., an increased appreciation for life, a sense of increased personal strength; Tedeschi et al., 1998), is associated with enhanced post-exposure functioning. Growth may be particularly germane to the treatment of Veterans with chronic PTSD whose symptoms ebb and flow across the lifespan in that clinically significant change (CSC) in PTG may be an enduring marker of clinical success. Although not directly targeted, in previous studies, trauma-focused treatments led to moderate mean effect size changes in PTG (e.g., Nijdam et al., 2018). In this archival analysis of a published non-inferiority trial comparing Adaptive Disclosure (AD; Litz et al., 2017) and Cognitive Processing Therapy – Cognitive Therapy (CPT-C; Walter et al., 2014) for U.S. Marines and Sailors with PTSD, we aimed to extend and replicate these studies. We used the Jacobsen and Truax (J&T; 1991) scheme for generating individual CSC indices of PTG. This level of analysis for CSC is preferrable to examining aggregate mean effect sizes because the latter hides effect size heterogeneity and excludes a standard way of judging the clinical significance of values. The J&T scheme categorizes participants as having negative (deteriorated or unchanged) or positive (improved or recovered) outcomes. We examined the frequencies of CSC in PTG, collapsing across treatment arms and we compared these values with CSC outcomes in PTSD symptoms. We also looked at possible differences between arms; predicting a significantly higher proportion of positive PTG outcomes in the AD arm relative to CPT-C, as the additional emphasis AD places on functioning may be more likely to lead to PTG. On every PTG-Inventory (PTGI) subscale, we found that approximately 20% had CSC in PTG, while most participants (n = 67) were unchanged. When comparing CSC in PTG and CSC in PTSD, we found that 21.1% of those with a negative PTSD outcome (n = 38) had a positive outcome on the Spiritual Change subscale of the PTGI, compared to 3.4% of those with a positive PTSD outcome (n = 29; z = 2.09, p = 0.036). Furthermore, surprisingly, 12.5% of those in the CPT-C arm (n = 32) deteriorated on the Personal Strength subscale, compared to 0% of those in the AD arm (n = 36, z = 2.19, p = 0.03). These results suggest trauma-focused therapies that do not specifically target growth do not produce clinically significant gains in PTG in most cases. The positive main effect for Spiritual Change in negative outcomes and the deterioration in Personal Strength in CPT are nuances that need to be replicated. Research is needed to increase growth perhaps by targeting it directly among service members with PTSD, particularly given that growth is putatively an aspect of quality of life.