Date of Award


Degree Name

Doctor of Philosophy



First Advisor

Dr. C. Richard Spates

Second Advisor

Dr. Chair Scott Gaynor

Third Advisor

Dr. Lisa Baker

Fourth Advisor

Dr. Andrea Kozak


The present study sought to add to a growing base of research investigating approaches that facilitate the therapeutic effects of exposure-based therapy for social anxiety disorders. In particular, the approach involves the use of medication adjuvants that work in conjunction with therapeutic learning. This work translates findings from preclinical work to further our understanding of the neurobiological mechanisms that impact extinction learning. Among others, a promising method has been found with the use of D-cycloserine (DCS), a partial NMDA receptor agonist. Evidence of its positive impact in preclinical work has led to its application to clinical populations who suffer from anxiety disorders. The present study aimed to add to the treatment outcome literature in this area. The study utilized a double-blind placebo-controlled design and a 10-session exposure-based CBT protocol with a participant population who met criteria for social anxiety disorder. The treatment protocol allowed for successful termination criteria to be reached following session 5, as well as deployed an algorithm that relied on in-session distress ratings to determine if sufficient learning occurred in each session. The latter was used as a determining factor for administration of the active versus inactive ingredient (placebo) immediately following each session. Changes were investigated using the administration of pre-session self-report measures and in-session behavioral and process measures. Rate of treatment attrition, meeting early termination criteria, the comparative extent of changes on symptom measures early in treatment, and comparative extent of maintenance of gains comprised key indicators of outcome. Potential moderators of DCS’s effects were also investigated. Data were investigated using both Linear Mixed Modeling and single subject analyses to investigate the slope of change, the interaction of treatment over time, and to address process-related questions. Results showed some evidence of DCS enhancement, as seen by greater slopes of change and more stable change as compared to participants receiving placebo on some measures. These benefits were seen over the full course of therapy as opposed to early in treatment. Initial severity levels were implicated as potential moderators of treatment effect.

Access Setting

Dissertation-Open Access