The influence of thought suppression and cognitive load on intrusions and memory processes following an analogue stressor.

Ironic Process Theory and the role of thought suppression have been used in part to explain the phenomenon of intrusive memories in various disorders, including posttraumatic stress disorder. How thought suppression interacts with other cognitive processes believed to be instrumental in the development of traumatic intrusive memory is unclear. In an analogue study, thought suppression and cognitive processing was manipulated in 4 experimental groups after participants (n=80) viewed a trauma film. The impact of suppression was examined in relation to self-reported intrusive experiences as well as via more objective methods (word stem and dot probe tasks) to assess potential preferential encoding of negative material. Cognitive load appeared to undermine thought suppression ability, with these participants experiencing more intrusions over the week relative to participants in all other conditions. This group also showed greater priming to negative film-related words, and both suppression groups demonstrated enhanced memory for film-related content on recognition testing. Thought suppression mediated the relationship between negative interpretations of initial intrusions and later intrusions experienced over the week. The findings are discussed in the context of ironic process theory and cognitive models of posttraumatic stress.

Does post-event cognitive load undermine thought suppression and increase intrusive memories after exposure to an analogue stressor?

Ironic process theory has been used in part to explain the phenomenon of intrusive memories in various disorders including post-traumatic stress disorder. How thought suppression interacts with other cognitive processes believed to be instrumental in the development of traumatic intrusive memory was tested. In an analogue design 120 participants were randomised to five conditions, four of which also required participants to attempt to suppress intrusive memories after viewing a film of traumatic content. Participants in three conditions were also required to perform concurrent tasks that acted as a cognitive load during suppression. Intrusive memories were recorded during the experimental phase and at 1-week follow-up. Contrary to predictions, post-film processing did not undermine suppression success. There was some suggestion that post-film processing resulted in those participants experiencing intrusions of shorter duration than the no-suppression control group in two 5-minute intrusion monitoring intervals at the initial and follow-up phase of the experiment, but this was not reflected in a 1-week diary measure of intrusions. All experimental groups performed in a similar fashion in terms of memory testing of the film's content. The findings are discussed in the context of ironic process theory and cognitive models of post-traumatic stress.

The effect of cognitive load and hyperarousal on negative intrusive memories.

Clinical theories of post-traumatic stress suggest that encoding processes at the time of a trauma are critical in determining whether intrusive memories will develop. Potential mechanisms that might influence the development of intrusive memories were studied, as was objective memory performance. In an analogue design, 65 participants were randomised to three conditions (cognitive load, hyperventilation, and control), and then watched a film of traumatic content. Intrusive memories were recorded during the experimental phase and at 1-week follow-up. Support was found for the prediction that verbal cognitive load and hyperventilation would facilitate intrusion development immediately following exposure to the trauma film; however, this was not maintained at follow-up. Consistent with cognitive models of post-traumatic stress, thought suppression and the distress associated with intrusive experiences mediated the relationship between distress caused by the film and intrusions at 1-week follow-up. Objective memory testing indicated that the three experimental groups showed similar recall and recognition performance for the content of the film; however, relative to the control group, individuals in the cognitive load condition were significantly less able to place film scenes in the correct order.