Optimizing Exposure Therapy With Mental Rehearsal

Study Overview
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Brief Summary
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Treatment response rates for cognitive behavioral therapy (CBT) across anxiety disorders average approximately 50% post-treatment (Loerinc et al, 2015), evidencing significant 'return of fear', the re-emergence of a partially or fully extinguished fear (Rachman, 1989). Thus, recent research has amplified efforts toward improving treatment methodology in an attempt to optimize clinical outcomes. Many efforts have targeted exposure therapy, an evidence-based behavioral technique during which a patient is strategically and repeatedly exposed to his or her feared stimulus in an effort to generate new non-fear associations with that stimulus. One such effort involves mental rehearsal, where information is reinstated using either a cue from extinction training or imaginal recounting of previous successful exposures (Craske et al, 2014). Prior research has assessed the effects of mental rehearsal via reinstatement of the extinction context (i.e., treatment context) or of cues/items from the treatment context that may indicate safety (e.g., Mystkowski et al, 2006; Culver, Stoyanova, & Craske, 2011). However, this research has produced inconsistent results and contains an inherent limitation, as retrieval cues may become a safety signal and inhibit new learning (Dibbets, Havermans, & Arntz, 2008). In an effort to address these limitations, the current study recruits spider-fearful participants for a treatment trial consisting of exposures in conjunction with either a mental rehearsal intervention, or a control rehearsal intervention. The overarching goal of this project is to evaluate the extent to which a between-session, technology-guided mental rehearsal intervention may optimize exposure therapy outcomes. We also seek to evaluate potential mechanisms of mental rehearsal. Participants complete three laboratory visits, including two sessions of exposures with live spiders. Participants are randomized to either a mental rehearsal or control rehearsal condition to measure potential mechanisms and moderators of mental rehearsal. Laboratory-based assessments include measures of subjective, behavioral, and psychophysiological responses to spiders.

Detailed Description
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Return of fear is the re-emergence of a partially or fully extinguished fear (Rachman, 1989). Due to relatively low treatment response rates for CBT at post-treatment (Loerinc et al, 2015), this study seeks to assess the efficacy of mental rehearsal (MR) in a different, less context-dependent manner than prior efforts (e.g., Mystkowski et al, 2006; Culver, Stoyanova, & Craske, 2011). Participants in the MR condition rehearse the new learning contingency, that is, that their feared outcome did not occur when they approached a live spider. Violation of expectancies engenders new, secondary learning that competes with the older fear memory (Craske et al, 2008; Bjork, 2003). As secondary, non-fear learning is repeatedly retrieved, the original fear memory is gradually suppressed, rendering it less recallable in the future (Bjork, 2011). Thus, repeatedly retrieving non-fear learning acquired from exposures is purported to strengthen the non-fear memory and reduce symptoms of arachnophobia. MR is conducted between sessions in an effort to reduce short-term return of fear by enhancing consolidation of non-fear learning via rehearsal efforts in multiple environments/contexts. The overall aim of the current study is to evaluate a method for enhancing the effectiveness of exposure therapy, and more specifically, to test the extent to which a novel between-session mental rehearsal intervention may optimize treatment outcomes in individuals with excessive fear of spiders. An important secondary aim is to better understand cognitive and affective mechanisms underlying benefits of mental rehearsal. The experiment consists of three sessions, spanning 8-10 days. Session 1 begins with a pre-treatment assessment consisting of self-report questionnaires and a behavioral approach test (BAT) with a live spider. During the BAT, confidence and distress ratings are obtained and psychophysiological responses (i.e., SCR) are recorded. Participants then complete a series of exposures with a live spider. At Session 2 (two to three days later), participants return to complete a second series of exposures with a live spider. At Session 3 (five to seven days later), participants complete a post-treatment assessment with self-report questionnaires and BAT, again with concurrent confidence and distress ratings and psychophysiological recordings. Between sessions, participants are randomized to mentally rehearse information from exposures (i.e., MR) or from an unrelated recent academic experience (i.e., Control). MR exercises guide participants in retrieving and consolidating learning from exposures, emphasizing the inhibitory relationship between the conditioned stimulus (CS) and the unconditioned stimulus (US) (i.e., that approaching the spider did not result in their anticipated/feared outcome). Measures span self-report, behavioral, and psychophysiological data. Fear of spiders is assessed with self-reported symptoms and measures taken during pre- and post-treatment BATs. During each BAT, skin conductance response (SCR) serves as a physiological index of fearful arousal. Baseline SCR is collected during a two-minute period at the start of pre- and post-treatment assessments. At both BATs, anticipatory SCR is collected during a one-minute period immediately prior to starting the BAT, and SCR is then continuously recorded throughout completion of the BAT. In addition to SCR, number of steps completed (0 to 9) and repeated ratings of confidence, anticipatory distress, and maximum distress during the BAT serve as important indices of fear. Self-reported stress, sleep quality, aerobic exercise, and knowledge of spiders are assessed as potential moderators of mental rehearsal and symptom change. Post-exposure ratings of surprise, US expectancy, and generalization of non-fear learning will additionally be evaluated as treatment mechanisms.

Official Title
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Optimizing Exposure Therapy With Mental Rehearsal

Conditions
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Anxiety Disorders, Arachnophobia

Intervention / Treatment
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* Behavioral: Mental Rehearsal
* Behavioral: Exposure


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: English-speaking Elevated score on Spider Phobia Questionnaire (SPQ) Exclusion Criteria: Severe allergies to bees/spiders/insects

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Mental Rehearsal<br>Between-session rehearsal/retrieval exercises focused upon consolidating non-fear learning gained from exposures by prompting reflection of expectancy violation and rehearsal of the inhibitory association between the conditioned stimulus (i.e., spider) and unconditioned stimulus (e.g., bite/attack). | Behavioral: Mental Rehearsal<br>* After each exposure session, participants complete three rehearsal/retrieval exercises that involve viewing images of spiders and completing multiple-choice and free-response questions. Exercises involve retrieving information specific to the spider exposures, reflecting on the experience, and highlighting expectancy violation (i.e., that the participant's feared outcome did not occur).<br>* Other names: mental retrieval;Behavioral: Exposure<br>* All participants complete two exposure sessions. The first set of exposures consists of ten 30-second trials hovering one's hand 3 inches over a live tarantula. The second set of exposures consists of ten 30-second trials placing one's hand inside the spider's terrarium with all five fingertips touching the bottom.<br>|
| Active Comparator: Control Rehearsal<br>Between-session rehearsal/retrieval exercises focused upon an unrelated, recent academic experience. | Behavioral: Exposure<br>* All participants complete two exposure sessions. The first set of exposures consists of ten 30-second trials hovering one's hand 3 inches over a live tarantula. The second set of exposures consists of ten 30-second trials placing one's hand inside the spider's terrarium with all five fingertips touching the bottom.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Spider Phobia Questionnaire (SPQ; Klorman et al, 1974) | 31-item true/false questionnaire assessing symptoms of arachnophobia. Scores range from 0 to 31, with greater scores representing greater fear of spiders. Spider phobic individuals have obtained mean scores of 23.20 (SD = 2.90) and 23.76 (SD = 3.80) on the SPQ (Klorman et al, 1974; Murris & Merckelbach, 1996). | Change from baseline to post-treatment (i.e., 8-10 days) | 
| Behavioral Approach Test (BAT) steps | Number of test steps fully completed | Change from baseline to post-treatment (i.e., 8-10 days) | 
| SCR anticipation | Change in SCR from baseline to BAT anticipation | Change from baseline to post-treatment (i.e., 8-10 days) | 
| SCR across BAT steps | SCR during each 30-second test step fully completed | Change from baseline to post-treatment (i.e., 8-10 days) | 
| Confidence ratings | Repeated confidence ratings on a scale from 0 (no confidence) to 100 (complete confidence) recorded throughout BAT | Change from baseline to post-treatment (i.e., 8-10 days) | 
| Distress ratings | Repeated anticipatory and maximum distress ratings on a scale from 0 (no distress) to 100 (severe distress) recorded throughout BAT | Change from baseline to post-treatment (i.e., 8-10 days) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Depression Anxiety Stress Scales (DASS-21; Lovibond & Lovibond, 1995) | 21-item self-report measure that assesses severity of symptoms of depression, anxiety, and stress. We use scores on the Stress subscale, which consists of 7 items measuring chronic non-specific arousal (e.g., difficulty relaxing, nervous energy, agitation, irritability). The minimum score on this subscale is 0 and the maximum score is 42 (0-14 = normal, 15-18 = mild, 19-25 = moderate, 26-33 = severe, 34+ = extremely severe). | Baseline | 
| Pittsburgh Sleep Quality Index (PSQI; Buysse et al, 1989) | 18-item self-report measure that assesses sleep quality and disturbances over the past month. We use the global score, which sums seven component scores. Scores range from 0 to 21, with a score of 5 or greater indicating poor sleep quality. | Baseline | 
| Aerobic exercise | Brief 4-item self-report measure that assesses time spent doing scheduled and unscheduled aerobic activity during a typical week. | Baseline | 
| Surprise | Ratings of surprise on a 5-pt Likert scale (1 = not at all surprised, 5 = extremely surprised) concerning the outcome of exposures. Scores are averaged across two exposure sessions. Scores range from 1 to 5, with greater values indicating greater surprise with the outcome of exposures. | Session 1 and Session 2 (i.e., 3 days) | 
| US expectancy | Ratings of US expectancy on a 5-pt Likert scale (0 = not at all likely, 5 = extremely likely) concerning a participant's estimated likelihood of the feared outcome occurring with the same context and stimulus as in vivo exposures. Scores are averaged across two exposure sessions. Scores range from 1 to 5, with greater values indicating greater US expectancy post-exposures. | Session 1 and Session 2 (i.e., 3 days) | 
| Non-fear generalization | Ratings of US expectancy on a 5-pt Likert scale (0 = not at all likely, 5 = extremely likely) concerning a participant's estimated likelihood of the feared outcome occurring with a different spider outside the lab. Scores are averaged across two exposure sessions. Scores range from 1 to 5, with lower values indicating greater ability to generalize safety learning. | Session 1 and Session 2 (i.e., 3 days) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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anxiety, consolidation, extinction, mental rehearsal