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Abstract
Research has consistently demonstrated that use of avoidance strategies after exposure to potentially traumatic events (PTEs) is associated with dysregulation of intrusions and more severe symptoms of posttraumatic stress. However, there are indications from studies of cognitive regulation and other research that individuals who exhibit more severe posttraumatic symptoms may be less efficient at enacting avoidance strategies to their intended aim of inhibiting unwanted stimuli, relative to other trauma survivors. The aim of research presented in this thesis was to test the hypothesis that ability to complete avoidance strategies may moderate the relationship between use of avoidance after PTEs and the severity of intrusions and other posttraumatic symptoms.
Studies presented in Chapter 2 developed a psychometric measure of posttraumatic avoidance ability, and found that whereas attempts at avoidance and low ability to avoid were associated with more frequent intrusions, completion of avoidance and high ability to avoid were associated with less frequent intrusions. Research in Chapter 3 compared self-report ratings of avoidance ability to thought suppression performance. Results showed that participants with high avoidance ability were better able to sustain effects of suppression than participants with low avoidance ability. Studies described in Chapter 4 compared ratings of avoidance ability to performance on tasks of regulation of attention and memory, and found that ability to avoid corresponded with capacities for inhibition of trauma-related stimuli at encoding. Chapter 5 detailed experiments which tested the role of avoidance as a moderator of intrusions by manipulating use of avoidance strategies after exposure to a trauma film. Results indicated that disrupting or promoting use of avoidance can have different effects on the persistence of intrusions and other symptoms as a function of avoidance ability. Lastly, the study presented in Chapter 6 tested ability to inhibit stimuli both before and after exposure to a trauma film, and found that avoidance ability may be associated with pre-existing differences in encoding trauma-related stimuli. Together, the results indicated that ability to avoid is a significant moderator of the relationship between use of avoidance and severity of posttraumatic symptoms, and may be implicated in the control of unwanted reminders of trauma.