Perceived control and avoidance in posttraumatic stress

Despite much evidence concerning the importance of control over stressors in animal models of adaptation to stress, there is a dearth of experimental evidence for the role of controllability in posttraumatic stress disorder (PTSD). This study investigated whether perceived control over aversive stimuli influenced subsequent avoidance in a female community sample with and without PTSD symptomatology. Female participants (N=145) with high or low PTSD symptoms were randomized to receive instructions indicating either controllable or uncontrollable offset of aversive, positive, and neutral images; despite this perception, the actual duration of presentations was standardized in both conditions. Participants subsequently completed an emotional avoidance task. There was a significant group x condition interaction effect, such that those with PTSD symptoms who were told they lacked control displayed greater avoidance of the subsequent stressor relative to those told they had control. This pattern was not observed in those without PTSD symptoms. This finding suggests that ongoing experiences of uncontrollability may heighten psychological vulnerabilities implicated in PTSD.