Clinically Significant Change in Posttraumatic Stress Disorder Symptoms Is Associated With Lower Levels of Aggression After Residential Treatment Discharge.

Although the link between posttraumatic stress disorder (PTSD) and aggression has been repeatedly demonstrated, to our knowledge no research has examined whether PTSD symptom reductions are linked to less aggression after treatment. The current study aimed to address this gap in the literature by examining the association between reductions in PTSD symptoms and posttreatment aggression among 2,275 veterans in residential treatment for PTSD across 35 Veterans Health Administration sites. We estimated a multilevel model that examined the effect of clinically significant PTSD symptom change on aggression at 4-month posttreatment follow-up, and found significant within-site and between-site contextual effects of clinically significant changes in PTSD symptoms on follow-up aggression. Findings revealed that veterans who reported clinically significant changes in their PTSD symptoms had lower levels of aggression at follow-up than veterans at the same treatment site who did not report clinically significant PTSD change. After we controlled for individual clinically significant PTSD change, participants in treatment sites where the rates of clinically significant PTSD change were higher overall had lower levels of aggression at follow-up. The model explained over one-fourth of the variability in aggression, R2 = .26. Findings from the current study extend previous research that has shown associations between PTSD and aggression, by revealing that clinically significant change in PTSD during residential treatment is associated with less aggression at follow-up. These findings suggest that interventions that effectively reduce PTSD symptoms may also help reduce risk for aggression.