The effectiveness of psychotherapies for social anxiety disorder (SAD) is typically evaluated using self- and clinician-reported symptom change, while biomarkers of treatment response are rarely measured.
This randomized controlled trial aimed to evaluate the effectiveness of single-session group interventions for SAD - imagery rescripting and verbal restructuring versus waitlist control (WC). The imagery rescripting intervention guided participants to rescript autobiographical memories through visualization whilst the verbal restructuring intervention focused on thought challenging. Outcomes included changes in psychophysiological reactivity (heart rate variability and electrodermal responding) to social stress, and symptom-based measures (social interaction anxiety, negative self-portrayal, cognitive avoidance, repetitive negative thinking, memory modification, anxious behaviors).
Psychophysiological reactivity was selectively attenuated following imagery rescripting treatment, compared to verbal restructuring and control groups. The specific influence of the imagery-based intervention in modulating autonomic reactivity was evident across heart rate variability parameters, including the standard deviation of intervals between heartbeats, and high-frequency power - an indicator of parasympathetically mediated emotion regulation. Few group differences were observed across self-report measures.
The current study highlights the specificity of brief imagery-based interventions in influencing psychophysiological reactivity in SAD and establishes the sensitivity of objective markers of treatment response in quantifying change over symptom-based measurements.