(PS12-A15) Decentering: A Transtheoretical Mechanism for Treatment in CBT

Transdiagnostic mechanisms of treatment response have received increasing attention over the past decade. Decentering is one specific process identified as a possible contributing factor to reductions in distress across a variety of modalities (Hayes-Skelton & Lee, 2020). Originally proposed as a mechanism within ACT, decentering is defined as the ability to shift perspective from an egocentric position to that of an objective observer when evaluating internal experiences (e.g., thoughts, emotions). Recent work, however, has proposed that the ability to recognize thoughts and emotions as observable behaviors is also relevant to more traditional forms of CBT, suggesting decentering may serve as a transdiagnostic mechanism of response. The aim of the current project was to examine the effects of decentering on symptom reduction in response to brief analogs of ACT and cognitive therapy (CT).

Participants were university students (N = 120; 75.83% ciswomen) noting elevated social anxiety in an initial screener. Following the completion of baseline measures of social anxiety (Liebowitz Social Anxiety Scale [LSAS]) and decentering (Metacognitive Processes of Decentering Scale [MPoD]), students were randomized to one of three, 45 min interactive training conditions: ACT-based coping techniques for social anxiety (n = 45), CT-based skills (n = 37), and an education control providing information about social fear (n = 38). Follow-up measures were completed at 3- and 7-days post-training to monitor levels of decentering and social anxiety.

Mixed-factors ANOVA was used to evaluate change in social anxiety and decentering from baseline to 7-day follow-up across conditions. Regression models were used to examine decentering as both a moderator and a mediator of within-person change in social anxiety, consistent with Judd et al. (2001).

Mixed-factors ANOVA identified a Condition*Time effect on LSAS scores (p = .043). Reductions in social anxiety were observed for ACT (d = -.60), CT (d = -.73), and educational control (d = -.71) conditions from baseline to 7-day follow-up although reductions at 3-day assessment were especially prominent for CT. Mixed-factors ANOVA also identified a Condition*Time effect for MPoD decentering (p < .001). Significant increases in decentering were observed in the ACT condition (d = .71). No change was noted for CT (d = .10) or educational control (d = .10) groups.

Influences on within-group change in LSAS from baseline to 7-day follow-up included both moderating and mediating effects of decentering, consistent with Judd et al. (2001). Results identified moderating effects of overall MPoD on LSAS change (β = -.19, p = .048), with greater reductions in anxiety noted for those with greater levels of decentering. Change in MPoD failed to emerge as a mediator of reductions in LSAS over time (p = .097). Observed effects were similar across all training conditions.

Results indicated similar reductions in social anxiety in response to single-session interventions although increases in decentering were unique to ACT. While data failed to support decentering as a mediator of symptom change, results do suggest that global decentering may facilitate symptom improvement over the short term, irrespective of treatment modality.