title: Approaches to Elicit and Attenuate Conditional Reinstatement of Fear for Specific Phobia
Creators: name: Krisch, Kirra A
Publisher: name: Griffith University
Year: 2022
Subjects: subject: Virtual reality
subject: exposure therapy
subject: specific phobia
subject: return of fear
subject: anxiety
subject: case study
subject: multiple phobias

description: Exposure therapy is considered the most effective treatment for many of the anxiety disorders including specific phobia. Despite this, following successful exposure therapy many individuals experience return of fear symptoms. The return of fear following exposure therapy suggests that extinction does not result in a permanent unlearning of associations between a conditional stimuli (CS) and an unconditional stimuli (US). Reinstatement of fear is one proposed mechanism for return of fear. A standard reinstatement procedure involves a CS paired with an US during acquisition, the CS is presented alone during extinction, the US is presented without the CS in reinstatement, and then followed by test trials of the CS. Reinstatement of fear is observed in test. While there are extensive laboratory-based studies demonstrating reinstatement of fear, there is limited clinical research on the conditions that might elicit and attenuate the reinstatement effect. Re-exposure to aversive stimuli (e.g., pain) in a standard reinstatement procedure with fearful individuals could be considered an ethical problem due to the potential for causing harm and distress. It is common for individuals suffering from specific phobia to have multiple phobias, with approximately 75% of individuals fear more than one object or situation. There is limited research investigating individuals with multiple phobias. Furthermore, an unextinguished CS has elicited reinstatement of fear with rats termed conditional reinstatement, which potentially suggests that an untreated fear can elicit reinstatement of fear in clinical populations. Accordingly, the current thesis had three main aims. Firstly, to investigate whether an unextinguished CS will elicit reinstatement of fear. Secondly, whether exposure to an unextinguished CS can reduce reinstatement of fear. Thirdly, to extend the translational nature and generalisability of the reinstatement research by conducting a laboratory-based experiment, a clinical-analogue experiment, and a case study intervention. In addressing these aims, the first experiment involved a laboratory-based learning task in virtual reality with 360 degree footage of a golden orb weaver (e.g., CS extinguished), a fancy rat (e.g., CS unextinguished) and a water python (e.g., CS -) with non-clinical participants (N = 93). The results showed reinstatement of fear can be triggered by an unextinguished CS and subsequent extinction of this unextinguished CS can attenuate reinstatement, as indicated by conditioned heart rate responses and shock expectancy ratings. Reinstatement of fear was not found for the control group. The findings of the first experiment provided the first evidence of how an unextinguished CS elicited and attenuated reinstatement in a non-clinical sample. In translating this finding to fearful individuals, a clinical-analogue experiment was implemented with 50 individuals who experience moderate to high fear towards rats and spiders. Extending the findings of the first study, exposure to an untreated fear reinstated fear to a treated fear and following virtual reality exposure therapy (VRET) attenuated this reinstatement, across subjective units of distress (SUDs), avoidance ratings and conditioned heart rate responses. The third study implemented a case study method with a participant who met criteria for specific phobia of rats and spiders. The purpose of the N = 1 design was to test an intervention based on the previous two studies. No reinstatement of fear was found from post-treatment to follow up, as indicated by SUDs ratings, avoidance ratings or conditioned heart rate responses. Overall, the results of the three translational studies demonstrated how exposure to different aversive events can trigger reinstatement and exposure with multifarious stimuli may enhance the long-term effectiveness of exposure therapy for specific phobia. The clinical implications of the research program include the recommendation to conduct a comprehensive assessment of the number of feared objects and/or situations experienced by the client and to treat each individual fear through VRET or in vivo exposure therapy to reduce the occurrence of conditional reinstatement.