Experimental data resulting from study investigating methods to reduce the conditioned fear response, intrusion frequency and Post-Traumatic Stress Disorder (PTSD) symptoms after viewing trauma films. The research used an experimental design that combined conditioning and trauma film paradigms. All participants underwent the same fear conditioning paradigm where trauma film stimuli (unconditioned stimuli) were paired with neutral stimuli (conditioned stimuli). Participants were randomly allocated to one of three US devaluation groups: ‘update’, ‘exposure’ and ‘control’. Exposure and updating techniques are frequently used as components of psychological therapy for PTSD but their relative effectiveness is unclear. This study aimed to compare the effects of updating the meaning of the trauma films (update group), further exposure to the trauma films (exposure group) and viewing non-traumatic films of related content (control group) on the reduction of the conditioned fear response and analogue PTSD symptoms. This study also investigated whether individual differences in fear conditioning are associated with the development of PTSD symptomatology. Overall, the findings suggest that adding a cognitive update to a US devaluation process significantly reduces subjective distress ratings to fear conditioned stimuli as well as intrusion frequency and PTSD symptoms. Adding a cognitive update to US devaluation increased skin conductance response to the conditioned stimulus compared to further exposure to the films. In this study, having a larger conditioned acquisition response predicted higher intrusion frequency and distress and more PTSD symptoms.

Participants: Participants were recruited by poster or email advertisements. One hundred and fifteen participants met inclusion criteria and completed the experimental task: 28 males and 87 females. Two participants did not complete the follow-up questionnaires so were excluded from these analyses. All participants gave informed consent and were paid for their participation. Ethical approval was obtained from King’s College London to complete the study and to share the data in the UK data Archive. Procedure: The study consisted of a screening stage, experimental session and a one week follow-up period. The experimental session comprised two consecutive phases (1) acquisition and (2) US devaluation. During acquisition, all participants underwent a Pavlovian discrimination fear conditioning paradigm and then participants were randomly allocated to one of three US devaluation groups. Questionnaires were administered in the screening stage and at one-week follow-up. In the experimental session, subjects were instructed to pay attention to the computer screen and to try to work out the meaning of the CS+ and CS-. Trauma film stimuli were used as the US, a circle (0.5 inches in diameter) as the CS+ and a square (0.7 inches in length) as the CS-. At pre-determined points during the task, the CS+ and CS- appeared in the right hand corner of the screen for two seconds. The participant’s physiological and subjective responses to the CS+ and CS- were measured before and after each phase. All participants took part in the acquisition phase. During acquisition, participants watched a series of six short film clips with introductory narratives and the CS+s embedded within them. The films contained real-life footage of humans and animals in distress. Each film contained an introductory voice-over which gave a narrative and context for the film. The CS+ was inserted into the films to signal the most distressing part of the film. The length of the film clips ranged from 76 to 150 seconds, with a mean length of 108.5 seconds (SD=33.09). After watching the six trauma films, participants viewed an intensive presentation phase in which the image and sound bite from the parts of the films previously paired with the CS+ (the worst moments) were presented again with the CS+. In this phase, the CS- was paired with neutral images. The CS+ was presented 10 times and the CS- presented 6 times during this phase. The US was displayed for 3 seconds. In the US devaluation phase, participants were randomly allocated to one of three US devaluation groups: (1) update group (n=37): participants viewed the same films again but the introductory passage was elaborated to contain additional information about what happened to the protagonists in the films. (2) Habituation group (n=41): the trauma films with the introductory passages were viewed again by participants. (3) Neutral (n=37): participants viewed non-traumatic films of related content. Reinforced CSs were not presented in this phase. In the week following the experimental phase, participants were asked to complete an intrusion diary to record any spontaneously occurring memories that they experienced related to the film clips and to complete the follow-up questionnaires. Detailed documentation available in the thesis and paper listed below.