Using Latent Variable Mixture Modeling to Understand Differences between PTSD and Moral Injury

Jessica Colleen Tripp

Data is provided by the student.

Abstract

Posttraumatic stress disorder (PTSD) and moral injury (MI) are common reactions to trauma exposure, particularly serving in a combat zone. While previous research has shown that PTSD and MI exhibit similarities, no research has examined person-centered analyses that demonstrate whether there are groups of individuals with high PTSD and low MI and vice-versa. This study explored an underlying class structure that differentiated subtypes of Operation Iraqi Freedom/Operation Enduring Freedom/Operation New Dawn (OEF/OIF/OND) veterans based on PTSD symptom clusters and MI. Participants were 208 OEF/OIF/OND veterans (91% men; 81% Caucasian) who completed self-report measures via an online survey that was distributed via various social media websites. Several screening questions preceded the questionnaires to ensure non-veterans would not take the survey, and those who were eligible and completed the survey received a $10 Amazon gift card. Latent variable mixture modeling generated four groups using 7 indicator variables of PTSD symptom clusters (reexperiencing, avoidance, NACM, hypervigilance) and types of MI (Transgressions-Others, Transgressions-Self, Betrayal), and MANOVAs further explained group differences. Class 1 (Low PTSD/Low MI) group members demonstrated the lowest levels of attachment avoidance and anxiety, depression, anxiety, anger, shame, guilt, contempt, and hostility inward. Class 2 (High PTSD/High MI) endorsed high levels of attachment anxiety and avoidance, depression, anxiety, anger, shame, guilt, contempt, and hostility inward. Class 3 (Moderate PTSD/Low MI) showed lower levels of attachment avoidance and anxiety than Class 2, and levels of anxiety, depression, shyness, disgust, guilt, shame, anger, contempt, and hostility inward lower than Class 2 and 4. Class 4 (Moderate MI plus NACM & Hypervigilance) was unique in that it demonstrated low levels of PTSD reexperiencing and avoidance but moderate levels of NACM, hypervigilance, Transgressions-Self, and Betrayal, and high Transgressions-Others. This group was higher than Class 1 and 3 in anxiety, depression, shyness, disgust, guilt, shame, anger, contempt, and hostility inward. Classes were not differentiated by past or predicted altruism, compassion towards others, or posttraumatic growth. Results indicate MI may be a subtype of PTSD that does not occur alone. Ideas for future research and clinical implications are discussed, including whether PTSD treatments may address MI.