(PS11-A24) Treatment of PTSD Among Active Duty Service Members with a History of Head Injury: Is Additional Psychotherapy Warranted?

Introduction: Currently, there is conflicting evidence regarding how TBI can impact PTSD treatment response. Some studies show that additional and more severe acute and chronic symptoms can serve as barriers to engage in or benefit from treatment (Bryant, 2011; Haarbauer-Krupa et al., 2021; Laskowitz & Grant, 2016; Ragsdale et al., 2018; Wachen et al., 2022). Other studies have shown that TBI is not predictive of PTSD treatment outcome (Ragsdale & Voss Horrell, 2016; Sripada et al., 2013; Walter et al., 2014). A recent study testing variable-length cognitive processing therapy (CPT) in active duty military reported that history of head injury (HHI) did not predict treatment outcomes.  However, the study did not distinguish between HHI and probable TBI, nor did the study report on specific acute and chronic symptoms of TBI and the relationship to treatment response. To date, there is also no indication whether those with a history of TBI require additional therapy sessions to achieve similar outcomes compared to those without TBI. The aim of this study was to determine whether CPT, a gold-standard therapeutic intervention for PTSD, is effective for those who have experienced TBI. Moreover, we aimed to investigate whether those with TBI required significantly more sessions of CPT, compared to those without TBI.

Methods: One hundred twenty-six active-duty service members participated in a larger within-subject clinical trial (Resick et al., 2021), in which participants received CPT in a variable-length format. Participants could receive up to 24 CPT sessions, depending on their individual treatment response. Participants continued therapy until they reached good end-state, defined as a score on the PTSD Checklist (PCL) as below 20 points. A generalized linear mixed model (GLMM) with fixed effects of time, TBI classification, and the respective interaction was conducted. Significant interaction effects were also examined.

Results: Participants completed baseline measures of history of head injury (HHI; modified from Schwab et al., 2006), depression (PHQ-9; Kroenke et al., 2001), and PTSD (PCL-5; Weathers et al., 2013) at baseline. Participants also completed the PHQ-9 and PCL-5 at the one-month follow-up. A majority of the sample (n = 95) reported at least one head injury, most (n = 74) of which occurred during deployment. Head injury did not predict treatment response of depression, F (3, 1) = 27.358, p < .001, or PTSD, F (3, 1), = 35.084, p < .001. Moreover, there was no difference in the number of sessions needed to reach good end-state among individuals with TBI (M = 14.50 sessions) versus those without TBI (M = 11.79), t (42) = 1.68, p < .05.

Discussion: Overall, participants with a history of TBI responded similarly to CPT in terms of PTSD and depression symptoms, compared to those without a history of TBI. Moreover, those with TBI did not require additional sessions to achieve similar outcomes. These findings are promising, especially given statistically comparable PTSD remission rates across the two groups. However, participants’ TBI severity of TBI was most likely “moderate,” and more research is needed to examine how to best address PTSD for those with more severe TBI. Loss of consciousness is one factor that may interfere with the PTSD recovery process.