(PS11-B41) Structure and Correlates of Polytrauma Clinical Triad Symptom Severity

Rates of posttraumatic stress disorder (PTSD), mild traumatic brain injury (mTBI), and chronic pain are high amongst Veterans of the Armed Forces who have served since 9/11/2001. The polytrauma clinical triad (PCT) has been advanced as a construct to reflect the overlapping and intersecting relationships between these conditions. Extant research, however, does not address whether the PCT should be viewed as the additive effect of discrete concerns or as a unitary construct. Evidence based on diagnostic codes suggests that the PCT can be represented as a singular latent construct, but further knowledge is limited by the “use of dichotomous variables that only account[s] for whether a condition, service, or prescription was present/absent during the period examined [and] does not provide information about disease severity…” (Pugh et al., 2014, pp. 180). Indeed, understanding whether the PCT is in fact a single dimension along which Veterans vary and whether this variation is predictive of functional outcomes may be critical to the assessment and treatment of Veterans with comorbid symptoms of PTSD, mTBI, and chronic pain. N = 221 Veterans (n = 23 female, mean age = 37.2 years) with chronic pain and a history of TBI were administered the PTSD Checklist – DSM 5, the Rivermead Post-Concussion Symptoms Questionnaire, and the Pain Interference Subscale of the Brief Pain Inventory at baseline of a clinical trial for chronic pain treatment. Average pain ratings (0-10) were also collected. Using continuous symptom-level indicators, we found that a hierarchical latent factor model of PCT symptom severity displayed acceptable to excellent fit (χ² = 1038.090, df = 899, p = 0.001, χ²/df = 1.15; RMSEA = 0.027; SRMR = 0.081; CFI = 0.990; TLI = 0.989), suggesting that comorbidity between PTSD, mTBI, and chronic pain can be modeled as a latent dimension of symptom severity. After controlling for age, sex, years of education, and race/ethnicity, PCT symptom severity displayed a sizeable association with the presence/absence of a positive PHQ-2 screener (r = 0.656, p < 0.001), suggesting that those with greater PCT symptom severity are significantly more likely to screen positive for depression as part of routine clinical care. Further, we found that, even after controlling for PHQ-2 status, greater PCT symptom severity was significantly associated with greater likelihood of unemployment (b = 0.764, p = 0.010). Results provide theoretical justification for a unidimensional construct representing severity of PCT symptoms. Examining PCT symptom severity as a unified construct, rather than as the presence/absence of categorical conditions, may provide new avenues for intervening on a prominent pattern of comorbidity in post-9/11 Veterans.