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Abstract
Treatments that include an exposure component are generally considered to be the most efficacious treatments of social anxiety disorder. However less is know about the exact mechanisms of change in these treatments. To better understand these mechanisms, this study utilized growth mixture modeling to examine the pattern of subjective anxiety during the first four in-session exposures for 95 clients in either individual or group cognitive-behavioral treatment for social anxiety disorder. Both the individual and the group treatments were based on Heimberg's Cognitive Behavioral Group Therapy (Heimberg & Becker, 2002) or the subsequent individual therapy manual (Hope, Heimberg, Juster, & Turk, 2000). Over the course of therapy clients completed, on average, four in-session exposures that each lasted three to ten minutes. During each exposure session clients provided ratings of their subjective anxiety approximately every minute. The pattern of these subjective ratings were analyzed to see if there were distinct classes of clients in each exposure and whether class membership was related to immediate or intermediate outcome. This study also focused on elements of emotional processing theory (Foa & Kozak, 1986), specifically initial activation and within session habituation. Across the four exposures, clients initially expressed moderate anxiety that decreased across the exposure; however the first and subsequent exposures were differentially related to outcome. There appeared to be two distinct classes of individuals during the second and third exposures based on the variability in their individual anxiety ratings. One class reported consistent anxiety ratings across the exposure while the other report a number of fluctuations in anxiety. While not statistically significant, interesting outcome patterns based on class membership emerged. Few differences emerged between those in individual and group treatment. Implications for emotional processing theory, for dynamic systems theory, and for the methodology used in studying mechanisms of change are discussed.
