Keywords: Stress | Change Process / Mechanisms
Presentation Type: Symposium
Reduction in self-reported distress both within and between therapy sessions, often referred to as habituation or extinction, has been proposed as a core mechanism of change in exposure-based PTSD treatments (Foa & Kozak, 1986). Previous studies using peak and mean subjective units of distress (SUDS) ratings to examine extinction in these treatments have found mixed results. However between-session extinction has been more frequently and consistently linked to better post-treatment outcomes than within-session extinction (see Sripada & Rauch, 2015 for a review). The current study investigates the association between extinction and outcome with virtual reality exposure (VRE) therapy using hierarchical linear modeling (HLM) to assess within- and between-session SUDS trajectories. Participants were 129 US military veterans who had been deployed in Iraq or Afghanistan and were diagnosed with PTSD using DSM-IV criteria. Participants completed a mean of 5.2 (SD = 1.2) VRE treatment sessions as part of a randomized controlled trial of VRE augmented with d-cycloserine, alprazolam, or placebo. Within- and between-session extinction was measured using the SUDS-scale as reported by the patient in each session and outcome was measured using the clinician administered PTSD scale (CAPS-4). Hypotheses were tested using three-level hierarchical linear models, with SUDS measurements (level-one) nested within treatment session (level-two), nested within participant (level-3). HLM showed a positive linear relationship between time and SUDS within session (t = 13.54, p <0.0001), consistent with increasing within-session distress, and a negative linear relationship between time and SUDS between session (t = -7.74, p < 0.0001), consistent with between-session extinction. Steeper reductions in SUDS across treatment sessions was associated with percentage of CAPS reduction over treatment (t = -4.75, p < 0.0001) and being a treatment responder (t = -4.43, p < 0.0001). Change in SUDS within-session was not significantly associated with CAPS reduction or responder status. These findings suggest that participants tended to experience between-session extinction, but not within-session extinction, and that having more between-session extinction was associated with better therapy outcome in VRE. Between-session extinction may be an important mechanism of change in VRE, although more research on extinction in this treatment is needed. Implications for clinicians engaging in exposure-based therapies for PTSD and for treatment researchers will be discussed based on the current findings
Emory University School of Medicine
Saturday, November 18
1:45 PM – 3:15 PM
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