Testing the Efficacy of Theoretically Derived Improvements in the Treatment of Social Phobia

Transcription

1 Journal of Consulting and Clinical Psychology 2009 American Psychological Association 2009, Vol. 77, No. 2, X/09/$12.00 DOI: /a Testing the Efficacy of Theoretically Derived Improvements in the Treatment of Social Phobia Ronald M. Rapee and Jonathan E. Gaston Macquarie University Maree J. Abbott University of Sydney Recent theoretical models of social phobia suggest that targeting several specific cognitive factors in treatment should enhance treatment efficacy over that of more traditional skills-based treatment programs. In the current study, 195 people with social phobia were randomly allocated to 1 of 3 treatments: standard cognitive restructuring plus in vivo exposure, an enhanced treatment that augmented the standard program with several additional treatment techniques (e.g., performance feedback, attention retraining), and a nonspecific (stress management) treatment. The enhanced treatment demonstrated significantly greater effects on diagnoses, diagnostic severity, and anxiety during a speech. The specific treatments failed to differ significantly on self-report measures of social anxiety symptoms and life interference, although they were both significantly better than the nonspecific treatment. The enhanced treatment also showed significantly greater effects than standard treatment on 2 putative process measures: cost of negative evaluation and negative views of one s skills and appearance. Changes on these process variables mediated differences between the treatments on changes in diagnostic severity. Keywords: social phobia, treatment, cognitive processes The majority of empirically validated treatment packages for social phobia currently comprise a combination of exposure and cognitive restructuring as their principal components (Hofmann, 2007; Rodebaugh, Holaway, & Heimberg, 2004). Several metaanalyses have confirmed that exposure-based treatment packages, either in isolation or in combination with other components, have shown good efficacy (Fedoroff & Taylor, 2001; Feske & Chambless, 1995; Gould, Buckminster, Pollack, Otto, & Yap, 1997; Norton & Price, 2007). Overall, treatment packages comprising exposure and cognitive restructuring have produced changes of around 0.9 standard deviations at the end of treatment, and these changes have been maintained over follow-up periods from 3 to 12 months. Current models of the maintenance of social phobia have begun to provide fine-grained analyses of the cognitive processes involved in the maintenance of social phobia (Clark & Wells, 1995; Hofmann, 2007; Rapee & Heimberg, 1997). Some of the key cognitive processes include an overestimate of the likelihood and cost of negative evaluation, an excessively negative perception of Ronald M. Rapee and Jonathan E. Gaston, Centre for Emotional Health, Macquarie University, Sydney, Australia; Maree J. Abbott, Department of Psychology, University of Sydney, Sydney, Australia. This research was supported by National Health and Medical Research Council Grant to Ronald M. Rapee. We would like to acknowledge the assistance of Nicola Kemp and Anna Thompson in development of the treatments and measures; Jennifer Mitchell and Lexine Stapinski for project management; and Jennifer Allen, Leigh Carpenter, Amanda Gamble, and Sarah Perini for research assistance. The many excellent therapists included the above plus David Bonsor, Leah Campbell, Lissa Johnson, Susan Kennedy, Natalie Robinson, and Julie Sposari. Correspondence concerning this article should be addressed to Ronald M. Rapee, Department of Psychology, Macquarie University, Sydney, NSW, Australia, Ron.Rapee@mq.edu.au the self, attentional bias toward this negative self appraisal (or toward external indicators of negative evaluation), and the use of subtle behavioral strategies that reinforce the negative self perception. Empirical evidence has demonstrated support for the importance of these processes (e.g., Heinrichs & Hofmann, 2001; Musa & Lepine, 2000; Rapee & Abbott, 2007). Of clinical relevance, several studies have begun to demonstrate that social anxiety can be reduced through direct manipulation of these psychological factors (Bögels, 2006; Garcia-Palacios & Botella, 2003; Harvey, Clark, Ehlers, & Rapee, 2000; Kim, 2005), although not all results have been consistent (Rodebaugh & Chambless, 2002; Smits, Powers, Buxkamper, & Telch, 2006). A more recent focus onto schema-based interventions has also begun to be applied to the management of social phobia (Pinto-Gouveia, Castilho, Galhardo, & Cunha, 2006) and is consistent with the personality-like features of the disorder (Rapee & Spence, 2004). Incorporation of these principles into clinical management programs has received little empirical evaluation. The main exception has been Clark s group in the United Kingdom and their collaborators who have reported a few trials over the past 5 years that utilized what could be described as an enhanced cognitive behavioral therapy (CBT) model of social phobia treatment (Clark et al., 2003, 2006; Stangier, Heidenreich, Peitz, Lauterbach, & Clark, 2003). Effect sizes from this program have been impressive, indicating pre-to posttreatment changes of around 2 standard deviations on self report measures of symptoms (Clark et al., 2003, 2006). However, some applications outside of the core research team have produced considerably smaller effects (e.g., Stangier et al., 2003; around 1.2 standard deviations for individual application and 0.6 standard deviations for group application). The theoretical considerations described above and the promising effects obtained by Clark s group suggest that empirical comparison between treatments based on conventional or standard CBT and a CBT package enhanced with these additional, theoret- 317

2 318 RAPEE, GASTON, AND ABBOTT ically derived components is highly warranted. At present, one study has conducted such a comparison. Clark et al. (2006) compared their enhanced cognitive therapy package against a basic program consisting of exposure and applied relaxation. Results indicated significantly stronger effects for the enhanced package across all measures. However, this study did not compare the enhanced package against a more traditional treatment package consisting of exposure plus cognitive restructuring. In addition, it did not assess changes in any putative mechanisms of treatment efficacy, and hence it is not clear to what extent the enhanced cognitive therapy modified these theoretically important processes. The purpose of the current study was to determine whether a treatment package for social phobia that incorporated the newer generation of techniques would result in a greater reduction in social anxiety than a traditional package that focused entirely on verbal cognitive restructuring and in-vivo exposure. Because the comparison standard CBT condition used by Clark et al. (2006) did not include cognitive restructuring, which has long been considered key in the management of social phobia (Butler, 1985), and because they utilized applied relaxation, which has previously shown considerably smaller effects than other standard treatments (Fedoroff & Taylor, 2001), we included a comparison CBT condition that utilized a comprehensive combination of cognitive restructuring and in vivo exposure. Aside from early work by Heimberg et al. (1990), there have also been few comparisons of exposure-based treatments against nonspecific skills-based treatments. Hence, the current trial also included a comparison treatment that focused on relaxation and general stress management but did not include specific exposure and cognitive components aimed at modifying social threat appraisals. Method Participants Participants for the study were 195 individuals meeting Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM IV; American Psychiatric Association, 1994) criteria for social phobia, randomly allocated to one of three treatment conditions: (1) stress management, (2) cognitive restructuring and in vivo exposure (standard), and (3) cognitive restructuring and exposure enhanced with the additional strategies (enhanced). A planned sample size (N 160) was determined to allow a minimum difference of.50 standard deviation units to be expected to be detected at an alpha of.05 with 80% power (Faul & Erdfelder, 1992) for main effects. Participants were included if they were over 18 years and met criteria for social phobia as their main (or most interfering) disorder. To maximize external validity, we minimized exclusions. The only planned exclusions were problems requiring immediate attention such as clear suicidal intent, severe substance abuse or dependence, or florid psychosis which were assessed during the structured interviews. Concurrent pharmacotherapy or psychotherapy was allowed as long as dosages had been consistent for 3 months and there were no plans to change. No participants were in concurrent psychotherapy. However, 26.7% were taking medications for their anxiety. Diagnoses for Axis I disorders were made by graduate students in clinical psychology using a structured clinical interview: the Anxiety Disorders Interview Schedule for DSM IV (ADIS-IV; Di Nardo, Brown, & Barlow, 1994). All pretreatment interviews were recorded, and 30 were randomly selected for coding by a second rater for reliability. A principal diagnosis of social phobia was rated with high reliability (.86, p.001). Clinical severity of each disorder was rated on a 0 8 scale reflecting severity relative to other people with the disorder and life impact. The intraclass correlation for the clinical severity rating of the principal diagnosis among the current reliability sample was r.85 (95% confidence interval.68.93). Following treatment, all participants were reinterviewed with the ADIS-IV addressing all anxiety disorders plus any additional disorders that they met criteria for at pretreatment. Reliability for posttreatment interviews was not assessed. Among the current sample, 91.4% met criteria for the generalized subtype of social phobia. As would be expected, Axis I comorbidity was also high: 37% met criteria for an additional anxiety disorder (most commonly generalized anxiety disorder, 30%; specific phobia, 8%; obsessive compulsive disorder, 5%); 29% met criteria for an additional mood disorder (major depression, 17%; dysthymia, 11%); and 9% met criteria for another additional disorder (alcohol abuse, 3%). The mean age of the sample was 33.7 years (SD 11.1), and 51.8% were female. Measures Measures were included for two main purposes: first to assess clinical outcome and second to assess changes in relevant processes. All measures were administered at pretreatment and posttreatment. Outcome Measures In addition to the diagnostic measures described above, questionnaire measures were designed to tap two constructs: symptoms of social anxiety and life interference. Social Interaction Anxiety Scale (SIAS) and Social Phobia Scale (SPS; Mattick & Clarke, 1998). These companion scales assess the main fears and avoidance of social phobia, respectively focusing on interaction fears and more specific performance-based fears. They have excellent psychometric properties (Peters, 2000). Albany Panic and Phobia Scale Social Phobia subscale (APPQ-S; Rapee, Craske, & Barlow, 1994). This is a brief set of items designed to tap social fears that are relatively distinct from overlap with agoraphobic fears. Later examination has shown consistent factor structure, solid reliability, and clear concurrent validity (Brown, White, & Barlow, 2005). Life Interference Scale (LIS). To provide a measure of the life impact of individuals social fears, we asked respondents to indicate the impact of their fears on various components of their life including work, family life, and leisure activities using six Likert scales ranging from 0 to 8. The scales were summed to provide a total interference rating from 0 (no interference) to48 (maximum interference). Previous analysis in our center has shown that the six items show excellent internal consistency (.90), and the total correlates significantly with the 12-item Short Form Health Survey (Ware, Kosinski, & Keller, 1996) Mental Component subscale (r.56).

3 ENHANCED TREATMENT OF SOCIAL PHOBIA 319 Process Measures To assess the role of several putative psychological processes, we also had participants complete measures of the following processes at pretreatment and posttreatment. Self-focused attention. We assessed this construct using the seven public self consciousness items from the Self Consciousness Scale (Fenigstein, Scheier, & Buss, 1975) plus an additional six items designed for the current study to extend the scope of this measure. The additional items were based on face validity and aimed to assess the tendency to take an external, observer s perspective during interactions a construct that has been argued as central to the maintenance of social phobia (Hackmann, Surawy, & Clark, 1998). Items included the following: I try to see myself through other people s eyes, I am aware of people s reactions to me, and I wonder how I look to other people. For the current sample, internal consistency of the 13-item scale was.93, and it correlated moderately with the SIAS (r.56). Safety behaviors and subtle avoidance. The tendency to engage in subtle avoidance or safety behaviors during social interactions was assessed with the 32-item Subtle Avoidance Frequency Examination (Cuming et al., 2008). Items include speak softly, wear cool items so as not to sweat, and make excuses about your appearance. Psychometric data indicate that the measure has strong internal consistency (.91) and clear convergent and discriminant validity (Cuming et al., 2008). For the current sample, internal consistency of the scale was.90, and it correlated moderately with the SIAS (r.59). Negative mental representation of appearance and performance. We assessed the individual s overall perception of their abilities and appearance using a 15-item measure that was used in previous experimental research that tapped two related factors of perception of personal abilities and perception of personal appearance (Rapee & Abbott, 2006). Items included I look attractive, I am a good dancer, and others perceive me as boring. The measure has previously been shown to discriminate people with social phobia from nonclinical controls (Rapee & Abbott, 2006). For the current sample, internal consistency of the scale was.78, and it correlated moderately with the SIAS (r.53). Probability and cost of negative evaluation. A 13-item measure of the probability and cost of negative evaluation was developed from previous research (Foa, Franklin, Perry, & Herbert, 1996; J. K. Wilson & Rapee, 2005). Participants read hypothetical negative events and then rated (a) the likelihood that the event would occur to them (probability) and (b) how bad it would be if it did occur (cost). Items included you will blush while being introduced to a new person and you will be ignored by someone you know. Internal consistencies for the two sets of ratings were s.83 and.89, respectively, and they both correlated moderately with the SIAS (rs.53,.58, respectively). Core beliefs. A 20-item list of core beliefs relevant to social anxiety was developed, and participants were asked to rate the extent to which they generally believed each one. Items included I am unlovable, I am inept, and I am dumb/stupid. Internal consistency for the current sample was.95, and it correlated moderately with the SIAS (r.62). Treatment credibility. We assessed participants perceptions of the credibility of the treatment they were allocated to using three items based on the measure by Borkovec and Nau (1972). The measure was administered at the end of Session 1 and Session 4 of each treatment. Working alliance. The 36-item Working Alliance Inventory (Horvath & Greenberg, 1989) was given to all participants in Session 4 to assess the relationship, support, and collaboration that participants perceived from their therapists. Group attitudes. The 20-item Group Attitude Scale (Evans & Jarvis, 1986) was also given to all participants in Session 4 to assess each participant s sense of belonging, positivity, and commitment to the group. Behavioral Observation Assessment To provide an additional measure of treatment outcome, we had participants attend a laboratory session before and following treatment where they were asked to perform an impromptu speech. This assessment was conducted by a research assistant who was blind to group allocation and study hypotheses. Participants were instructed to deliver a speech about a topic of their own choosing to the experimenter and a video camera. Participants were allowed to talk on any topic aside from their participation in the research. They were given 2 min of preparation time and were instructed to talk for 3 min. Any participant who stopped in less than 3 min was briefly encouraged by the experimenter to continue, but if he or she refused, the postspeech measures were administered at that point. At pretreatment, a total of 8 participants refused to give the speech, and an additional 18 participants failed to complete the entire 3 min. At posttreatment, only 1 participant refused to give the speech, and an additional 14 participants failed to complete the entire 3 min. Participants completed several measures of relevance to other research (e.g., Rapee & Abbott, 2007). The main measure of relevance to the current study was an assessment of state anxiety during the speech. The measure comprised 10 items that were conceptually related to a sense of current anxiousness in relation to the speech (e.g., I felt nervous and I felt like stopping the speech ). Items were scored on a scale ranging from 0 to 4, and participants were instructed to complete the items indicating how they felt during delivery of their speech. Internal consistency of the 10 items in the current sample was.95. Conditions General Treatment Factors All three treatments were conducted in groups of approximately 6 participants. Therapists were clinical psychologists with specific expertise in the treatment of social phobia. In most cases, a graduate psychology student acted as cotherapist. All primary therapists conducted groups in each of the treatment conditions. Therapists received regular weekly supervision from Jonathan E. Gaston. Supervision was primarily focused on maintaining the treatment protocols and ensuring that relevant differences were maintained between conditions. Groups extended for 12, 2-hr sessions across 12 weeks. All three treatments followed manuals for the therapists and were supported by printed materials and handouts for participants. Standard Treatment Standard treatment comprised what would probably be referred to as a basic cognitive behavioral package. Treatment was

4 320 RAPEE, GASTON, AND ABBOTT based loosely on previous cognitive behavioral programs (e.g., Heimberg et al., 1990; Mattick & Peters, 1988) but was restricted to cover purely cognitive restructuring and in vivo exposure. Cognitive restructuring followed principles described by Beck (e.g., Beck, Emery, & Greenberg, 1985) and was based on refutation of unrealistic beliefs through consideration of evidence. Extension to broader overarching constructs (such as schemas) or to cognitive processes (such as attentional bias or use of hypothesis testing) was not done. In vivo exposure exercises were conducted in a graduated and systematic fashion and were individually tailored to target the specific social fears of each participant. The rationale was based on the principles of habituation. Participants were directed to develop individualized hierarchies and to conduct systematic exposure between sessions. Assertiveness skills and some general social skills practice were also included toward the end of the program. Enhanced Treatment The enhanced treatment was developed by members of our unit on the basis of a similar earlier program (Rapee & Sanderson, 1998). Sessions covered cognitive restructuring and in vivo exposure in a similar manner to the standard treatment, although the rationale for exposure followed more of a cognitive, evidencegathering concept, and the overlap between cognitive restructuring and in vivo exposure was emphasized through use of hypothesis testing. Data gathering was extended to incorporate identification and refutation of underlying beliefs and overarching life scripts by identification of these broader beliefs followed by examination of evidence from across the individual s life. In vivo exercises also included elimination of safety behaviors and subtle avoidance as well as realistic appraisal and feedback of performance. Participants also practiced exercises to train controlled attentional resources away from negative evaluation and the self and toward the task at hand through meditation-type exercises and in vivo practice of focusing of attention to different features of the environment. Stress Management The purpose of the treatment was to provide credible procedures that were aimed at management of stress and general anxiety but did not specifically address social threat concerns or fears of negative evaluation. The provided rationale was based on teaching management of the fight or flight response. Specific components were mostly focused on training in relaxation skills but also included problem solving, time management, and healthy lifestyle habits. Participants were encouraged to apply relaxation and other skills when feeling stressed, but they were not instructed to systematically approach feared objects while relaxing. 1 Treatment Integrity All treatment sessions were audiotaped, and a random sample was coded for content. Of a total of 360 possible treatment sessions, 60 (16.7%) were coded. Coders were therapists who had been trained in and ran the treatments (although naturally they did not rate their own groups), and they were blind to the specific condition that they were rating. Coding was based on a measure that listed 34 techniques or types of information that were included in one or more of the treatment conditions. Coders listened to the entire session and checked a given item when they heard that technique or information covered by the therapist. A research assistant later unblinded the allocated condition and determined whether the checked items were correct with respect to the allocated condition (i.e., were part of the allocated treatment condition) or incorrect (i.e., should not have been included in that condition). For example, the item discouraged use of safety behaviors would have been rated correct in a session from the enhanced condition but incorrect if it appeared in a session from the other two conditions, whereas the item look for evidence for or against clients thoughts would have been marked correct in either the enhanced or standard conditions but incorrect if it appeared in the stress management condition. Each treatment condition had a different number of possible correct and incorrect items from the checklist. Hence, to provide a simple indication of treatment integrity, we calculated the number of correct components identified by each rater as a percentage of the total number of components identified. In other words, if only correct components were identified, the percentage would have been 100%; if equal correct and incorrect components had been identified, the percentage would have been 50%. Raters also guessed which of the treatment conditions the tape they listened to was from. Eighteen (30%) of the integrity tapes were coded by a second rater who was blind to treatment condition. There was complete agreement between pairs of raters on the proportion of correct components for 17 of the 18 sessions (there was no variance for one cell, and hence statistics could not be calculated). Pairs of raters agreed on the guessed condition represented by each tape in 17 of the 18 cases (.91, p.01). Procedure The procedures were approved by the Human Research Ethics Committee, and all participants gave informed consent. Potential participants contacted the Centre for Emotional Health at Macquarie University (Sydney, Australia) between September 2002 and February 2005 through usual referral sources, including general practitioners, mental health professionals, occasional media coverage, and word of mouth. They were screened via telephone, and those who appeared to have anxiety-related difficulties were invited in for a structured interview and behavioral assessment. A total of 494 participants were assessed with structured interview, of whom 265 did not meet study criteria, and an additional 34 were randomly allocated to another study. The remaining 195 who met inclusion criteria were randomly allocated to one of the three conditions. Randomization was done on a group basis by the project manager via a preassigned random schedule. Participants were allocated in blocks of six to eight to allow for group delivery and group start times. An individual participant was not allocated to a condition until after he or she was accepted into the study that is, after initial diagnostic and questionnaire assessment. Following the structured diagnostic interview, participants completed the questionnaire measures and were scheduled for the behavioral assessment, usually within 1 week. Treatment generally began 1 Copies of the manuals can be obtained from Ronald M. Rapee or Jonathan E. Gaston.

5 ENHANCED TREATMENT OF SOCIAL PHOBIA 321 within the following few weeks. At the conclusion of treatment (12 weeks), questionnaire, diagnostic interview, and laboratory measures were repeated and were conducted by clinicians who were blind to participants group allocations. Because of ethical requirements, participants who requested additional treatment were then offered the enhanced program, and the theoretically relevant comparison ended. In principle, this offer was open to all participants; however, in reality, therapists did not generally extend the offer to participants in the enhanced condition because they had already received this treatment. Statistical Analysis Primary outcomes for this trial were a reduction in clinical diagnoses and severity of social phobia as assessed by the ADIS- IV, reduction in social phobia symptoms, and reduction in selfrated life interference. In addition, analyses were conducted to examine differences between treatments on reductions in theoretically meaningful cognitive variables, and mediation of changes in social anxiety by these cognitive variables was also examined. To reduce the number of repetitive statistical tests, we calculated a social phobia symptom composite score by totaling standardized scores on the SPS, SIAS, and APPQ-S. This variable is hereafter referred to as social anxiety. Analyses were based on intention-to-treat, including all participants who entered the trial. Every attempt was made to collect 12-week (posttreatment) data on all participants, even those who did not complete treatment. Analysis of data was also conducted on the basis of participants who completed at least three sessions of treatment and returned posttreatment data (N 160; 82.1%). The pattern of means and effect sizes was identical to the intention-to-treat analyses and, hence, is not described further. The flow of participants through the study is presented in Figure 1. We examined differences between treatments in the reductions on continuous data using hierarchical mixed models containing random intercept and random slope terms as well as fixed effects for treatment received (Gibbons et al., 1993). Because randomization was based on treatment groups, the individual treatment group that each participant was allocated to was entered into each analysis as a first level effect followed by the interaction between group and individual. Finally, to examine the role of specific cognitive factors in mediating treatment effects, any process variables that showed a significantly greater change in the enhanced condition were subjected to mediation analyses to assess their role as mediators of the change in diagnostic severity associated with the enhanced treatment. All analyses were conducted with SPSS Version Figure 1. Consolidated Standards of Reporting Trials (CONSORT) style flow chart of study participants.

6 322 RAPEE, GASTON, AND ABBOTT Results Demographic data on the sample broken down across the allocated groups are presented in Table 1. As can be seen from the table, the groups did not differ significantly in demographic features or on their main diagnostic and clinical characteristics. Treatment Integrity and Attitudes to Therapy The percentage of correct components relative to total identified by the raters was compared between conditions. There was no significant difference across the three conditions: enhanced (M 99.7%, SD 1.5), stress management (M 95.5%, SD 11.1), and standard (M 98.9%, SD 4.7), F(2, 59) 2.39, p.10. As a better indication, the mode and median of percentage of correct components in each condition was 100%, and incorrect components (i.e., less than 100%) were only identified in five tapes (8.3%). Hence, there was very little contamination between conditions. There was also significant agreement between the condition that the raters guessed the selected tape was from and the actual condition it had been selected from: enhanced, 96.6% correct guesses; standard, 94.4% correct guesses; and stress management, 84.6% correct guesses (.89, p.001). We compared treatment credibility across groups at the two assessment times (Sessions 1 and 4) using a repeated measures analysis of variance. As can be seen in Table 1, the groups did not differ significantly on credibility of treatment, F(2, 126) 0.00, p.97, partial 2.01, and there was not a significant Group Time interaction, F(2, 126) 0.25, p.78, partial Working alliance measured in Session 4 was compared between the groups and showed no significant differences, F(2, 150) 0.71, p.49, Similarly, there was no significant difference between the groups on the attitudes toward the group, F(2, 150) 0.79, p.46, Diagnostic Data We compared the number of participants who no longer met criteria for a diagnosis of social phobia at the end of treatment across conditions using chi-square. When data at posttreatment were missing, the pretreatment diagnosis was substituted. There was a significant overall difference between groups, 2 (2, N 195) 7.28, p.026. Follow-up pairwise chi-squares indicated that the enhanced group (n 29; 40.8%) and the standard group (n 23; 34.8%) did not differ significantly, 2 (1, N 137) 0.52, p.470, but both showed significantly greater proportion of diagnosis free participants than the stress management condition (n 11; 19.0%), 2 (1, N 129) 7.14, p.008, 2 (1, N 124) 3.91, p.048, respectively. Clinical Significance To determine the clinical significance of effects, we determined the percentage of participants in each group who showed a reliable change that placed them closer to the mean of a community control group than to the mean of the current socially phobic sample at posttreatment (Jacobson & Truax, 1991). These clinically significant cutoffs were determined for the SPS and SIAS (Mattick & Clarke, 1998) because these are two of the most widely and consistently used measures of social anxiety. This required a two-step process as follows. First, cutoff scores were calculated on the basis of Formula c reported by Jacobson and Truax (1991). The mean scores for the SPS and SIAS reported by Mattick and Clarke (1998) for their community sample were used and compared to the mean scores for each measure reported in the current sample. This resulted in clinical significance based on the SPS at a score of 23 or below and on the SIAS at 35 and below. Next, reliable change indices were calculated for each participant on the basis of the 12-week retest reliability reported by Mattick and Clarke. Thus, clinical significance for a given participant was defined as showing a reliable change from pre- to posttreatment plus reaching a posttreatment absolute score that was below the cutoff for clinical significance. According to these criteria, the following proportions of participants demonstrated clinically significant effects at posttreatment in each condition: SPS enhanced (42.4%), standard (22.0%), stress management (10.2%), 2 (2, N 158) 15.01, p.001; SIAS enhanced (31.1%), standard (18.0%), stress management (12.2%), 2 (2, N 160) 6.26, p Table 1 Descriptive Data Across the Three Groups Variable Enhanced Standard Stress management Statistic Mean age (SD) 33.2 (9.4) 32.2 (11.3) 35.4 (12.0) F(2, 192) 1.42, p.24, 2.02 Female (%) (2, N 195) 1.61, p.49 Never married (%) (4, N 187) 2.59, p.63 University (%) (4, N 185) 7.66, p.11 Employed (%) (2, N 187) 0.65, p.73 Avoidant PD (%) (2, N 195) 3.07, p.22 Additional Axis I (%) (2, N 195) 1.14, p.57 Medication (%) (2, N 195) 1.50, p.48 Treatment credibility, M (SD) Week (9.8) 22.5 (4.6) 23.1 (3.3) F(2, 153) 0.10, p.90, 2.01 Week (4.9) 23.4 (4.8) 22.3 (4.2) F(2, 135) 0.74, p.48, 2.01 Working alliance, M (SD) (26.57) (21.83) (19.45) F(2, 150) 0.71, p.46, 2.01 Group attitudes, M (SD) (19.08) (23.07) (21.42) F(2, 192) 0.79, p.46, 2.01 Note. PD personality disorder.

7 ENHANCED TREATMENT OF SOCIAL PHOBIA Follow-up pairwise chi-squares indicated that the enhanced group showed significantly more clinically significant change than the standard group on both the SPS, 2 (1, N 137) 9.32, p.002, and the SIAS, 2 (1, N 137) 5.56, p.018. The enhanced group also showed more clinically significant change than the stress management group on both the SPS, 2 (1, N 129) 18.26, p.001, and the SIAS, 2 (1, N 129) 7.39, p.007. The standard CBT and stress management groups did not differ significantly on either the SPS, 2 (1, N 124) 2.39, p.122, or the SIAS, 2 (1, N 124) 0.25, p.619. Continuous Clinical Measures Mixed model analysis comparing the three treatments across time on the clinician rating of social phobia severity showed a significant main effect of condition, F(2, 23.9) 3.60, p.043; a significant main effect of time, F(1, 184.8) 170.0, p.001; and a significant Condition Time interaction, F(2, 184.7) 8.01, p.001. Follow-up tests demonstrated significant Condition Time interactions comparing enhanced treatment with standard treatment, t(186.3) 2.84, p.005; and enhanced treatment with stress management, t(181.5) 3.80, p.001; but not between stress management and standard treatment, t(186.4) 1.00, p.317. Estimated marginal means, standard errors, and effect sizes are presented in Table 2. The three treatment conditions were also compared across time on the composite measure of social anxiety. There was a significant main effect of condition, F(2, 185.6) 3.70, p.027; a significant main effect of time, F(1, 168.7) , p.001; and a significant Condition Time interaction, F(2, 168.7) 5.73, p.004 (see Table 2). Follow-up tests did not demonstrate a significant Condition Time interaction comparing enhanced treatment with standard treatment, t(169.2) 0.45, p.651; however, significant effects were demonstrated between enhanced treatment and stress management, t(167.5) 3.20, p.002, and between standard treatment and stress management, t(169.3) 2.68, p.008. Examination of effects on the LIS indicated no significant main effect of treatment condition, F(2, 184.5) 1.13, p.327; however, examination of effects on the LIS indicated a significant main effect of time, F(1, 169.3) , p.001, which was qualified by a significant Condition Time interaction, F(2, 169.3) 4.07, p.019 (see Table 2). Follow-up tests demonstrated no significant Condition Time interaction comparing enhanced treatment with standard treatment, t(169.9) 0.80, p.425; however, a significant effect was demonstrated comparing enhanced treatment with stress management, t(168.0) 2.80, p.006, and a trend approaching traditional levels of significance comparing standard treatment and stress management, t(170.0) 1.97, p.051. Speech Task We compared state anxiety in response to the brief impromptu speech pre- and posttreatment between the three treatment conditions using a mixed model analysis. There was no significant main effect of treatment condition, F(2, 167.3) 0.56, p.575; however, there was a significant main effect of time, F(1, 134.5) 69.91, p.001, and a significant Condition Time interaction, F(2, 134.5) 3.17, p.045 (see Table 2). Follow-up tests demonstrated a trend approaching traditional levels of significance comparing enhanced treatment with standard treatment, t(136.7) 1.67, p.098, and a significant interaction between enhanced treatment and stress management, t(132.7) 2.44, p.016. The interaction between standard treatment and stress management was not significant, t(134.0) 0.70, p.488. Process Measures Mixed model analysis comparing the three treatments across time on the measure of probability of negative evaluation showed a main effect of condition, F(2, 25.7) 4.31, p.024; and a significant main effect of time, F(1, 165.6) 39.67, p.001; but failed to show a significant Condition Time interaction, F(2, 165.6) 0.35, p.702. Marginal means, standard errors, and effect sizes are presented in Table 3. Comparison between the three treatments across time on the measure of the cost of negative evaluation showed a significant main effect of condition, F(2, 185.5) 9.25, p.001; and a significant main effect of time, F(1, 173.1) , p.001; as well as a significant Condition Time interaction, F(2, 173.1) 6.68, p.002 (see Table 3). Follow-up tests demonstrated a trend approaching significance for the Condition Time interaction comparing enhanced treatment with standard treatment, t(173.8) 1.89, p.060; a significant interaction comparing enhanced treatment with stress management, t(171.5) 3.65, p.001; and a trend approaching traditional levels of significance for standard treatment versus stress management, t(173.9) 1.76, p.080. Table 2 Estimated Marginal Means and Standard Errors for Continuous Outcome Measures Over Time Measure Treatment type Enhanced Standard Stress management M SE Effect size M SE Effect size M SE Effect size Clinician-rated diagnostic severity Pretreatment Posttreatment Social anxiety composite Pretreatment Posttreatment Life Interference Scale Pretreatment Posttreatment State anxiety to speech Pretreatment Posttreatment Note. Effect size expressed as Cohen s d, on the basis of pre post treatment change within conditions.

8 324 RAPEE, GASTON, AND ABBOTT Table 3 Estimated Marginal Means and Standard Errors for Process Measures Over Time Measure Treatment type Enhanced Standard Stress management M SE Effect size M SE Effect size M SE Effect size Probability of negative evaluation Pretreatment Posttreatment Cost of negative evaluation Pretreatment Posttreatment Self-focused attention Pretreatment Posttreatment Negative mental representation Pretreatment Posttreatment Use of safety behaviors Pretreatment Posttreatment Core beliefs Pretreatment Posttreatment Note. Effect size expressed as Cohen s d, on the basis of pre post treatment change within conditions. Comparison between the three treatments across time on the measure of self-focused attention showed no significant main effect of condition, F(2, 183.0) 2.28, p.106, but a significant main effect of time, F(1, 164.5) 46.85, p.001. However, the Condition Time interaction did not reach significance, F(2, 164.4) 0.91, p.403 (see Table 3). Comparison between the three treatments across time on the measure of the negative mental representation showed no significant main effect of condition, F(2, 23.5) 1.70, p.205. However, there was a significant main effect of time, F(1, 162.6) 85.41, p.001, as well as a significant Condition Time interaction, F(2, 162.6) 8.56, p.001 (see Table 3). Follow-up tests demonstrated significant Condition Time interactions comparing enhanced treatment with standard treatment, t(163.0) 2.37, p.019, and enhanced treatment with stress management, t(161.8) 4.10, p.001. However, the interaction between standard treatment and stress management only approached traditional levels of significance, t(163.0) 1.75, p.083. Comparison between the three treatments across time on the measure of the safety behaviors failed to show a significant main effect of condition, F(2, 181.0) 1.83, p.163, or a significant Condition Time interaction, F(2, 163.1) 2.06, p.131. However, there was a significant main effect of time, F(1, 163.1) 104.0, p.001 (see Table 3). Finally, comparison between the three treatments across time on the measure of core beliefs showed no significant main effect of condition, F(2, 182.2) 1.32, p.269. However, there was a significant main effect of time, F(1, 154.6) 47.50, p.001, but the Condition Time interaction was not significant, F(2, 154.6) 1.00, p.372 (see Table 3). Mediation of Treatment Effects Given the significant Condition Time interactions on two of the process measures negative mental representation and cost of negative evaluation an analysis was run to examine whether changes in these process variables might mediate between the differences between treatments and change in outcome. The unique effect of the enhanced treatment program was represented by a dummy code on allocated treatment condition that compared the enhanced condition against the other two conditions combined. Change in treatment outcome was represented by a difference score from pretreatment to posttreatment on the clinician s rating of diagnostic severity. Change scores were also used to represent change in the two process variables. Test of mediation for multiple mediators was based on the macro and principles described by Preacher and Hayes (2004, 2007). The difference between treatments accounted for significant variance in the change in diagnostic severity, B 1.02, SE 0.27, p.001 (Path c); however, after the two process variables were included in the regression, this path was markedly reduced, B 0.52, SE 0.25, p.041 (Path c ). The total indirect path from the difference between treatments to change in diagnostic severity via change in mental representation and change in cost of negative evaluation was significant, B 0.50, SE 0.15, p.001. Hence, significant, partial mediation was demonstrated. The overall regression accounted for 29% of the variance in change in diagnostic severity, F(3, 149) 20.46, p.001. Discussion The overall pattern of results indicated that the enhanced treatment was generally superior to a traditional skills-based treatment, although the traditional treatment was efficacious and generally superior to nonspecific stress management. The general pattern of results and the effect sizes shown in Tables 1 and 2 indicated that both exposurebased treatments showed good efficacy and that the standard CBT was significantly better than general stress management on two main outcome measures. In fact, the traditional cognitive restructuring plus exposure treatment appeared to show slightly larger effects than has been demonstrated in some previous research. Early studies that used pure exposure or exposure plus cognitive restructuring have resulted in effect size changes of around 0.9 on self-reported symptoms of social phobia (Fedoroff & Taylor, 2001; Feske & Chambless, 1995; Gould et al., 1997). In the current study, the standard treatment produced changes of over 1 standard deviation on the main outcome measures, which compares favorably with these early studies. Nevertheless, despite the demonstrated efficacy for the standard treatment, the enhanced program showed slightly larger effects across measures, and these differences reached significance on several key variables.

9 ENHANCED TREATMENT OF SOCIAL PHOBIA 325 Specifically, the enhanced treatment showed significantly greater changes than the standard treatment on the clinician s rating of diagnostic severity and the measures of clinical significance, and it also showed a trend toward statistical significance on the observational measure of anxiety in response to a speech. An inability to demonstrate statistical significance across some of the other measures may have been due to the group format, brevity of the program, or sample size. The delivery of all treatments in group format may have limited variance between treatments. There is some evidence that group treatment of social phobia may not produce as large effects as individual delivery (Mortberg, Clark, Sundin, & Wistedt, 2007; Stangier et al., 2003). This might be particularly the case for the enhanced treatment that depends quite heavily on individualization of treatment components, especially performance feedback, exploration of schemas, and dropping of safety behaviors. For maximum efficacy, these components depend on tailoring of their application to an individual s specific circumstances, and this is difficult to do in the context of group delivery. The current program was also somewhat briefer than similar programs conducted by Clark and his colleagues (Clark et al., 2003; Mortberg et al., 2007), and selection of participants was slightly less specific. Consistent with these factors, the effect sizes found in the current study were somewhat smaller than reported in studies by Clark s group (Clark et al., 2003, 2006). Delivery of treatment in a group format may have also provided some in vivo exposure for all participants, further reducing variance between conditions. In some ways, then, the demonstration of larger effects in the enhanced program than the other treatments on several measures is even more impressive. Another factor that may have influenced outcomes was the competence of therapists. It is unlikely that therapists were not competent because they were clinical psychologists with experience in management of social phobia and received supervision from an expert in anxiety and social phobia. They also demonstrated excellent adherence to the treatment protocols. However, adherence is not the same as competence, and it is a limitation of the study that competence was not assessed. Demonstrating competence is extremely difficult because there is no gold standard for delivery of these techniques. In addition, given that the traditional program essentially formed a subset of the enhanced program, it is less likely that lack of competence influenced differences between these key conditions. However, variable therapist competence in any of the treatment conditions may have influenced the results in a variety of directions, and future studies would benefit from development of competence measures. The current study represents one of the larger clinical trials for the management of social phobia. Nevertheless, even this trial only had sufficient power to detect a moderate effect size difference between groups on main effects and even larger effect sizes for the relevant interactions. As a result, we did not control the experiment-wise Type 1 error rate, and this provides a limitation to the study. Strict control of the Type 1 error rate may have prevented some differences between the active treatments to reach significance, yet we believe that this would not be a reasonable conclusion on the basis of examination of the overall pattern of results. Hence, we chose to maintain a balance between Type 1 and Type 2 errors. Ideally, a study of this kind would include multiple sites and a sample size of several hundred. Only with such samples will researchers be able to truly gauge the effects of relatively subtle improvements to already active treatments. Perhaps the greatest interest from the current study was in the effects of treatment on process measures. Given that the enhanced treatment was designed to modify theoretically important maintaining factors, the key question of interest is whether it did. Several factors included in maintenance models of social phobia (Clark & Wells, 1995; Rapee & Heimberg, 1997) were assessed. Unfortunately, given the lack of well-established measures for most of these factors, several of the measures were newly developed and, hence, had little established reliability or validity. However, such a limitation would be conservative with respect to the hypotheses because limited reliability in particular would reduce the power of the study to demonstrate relationships. As a result, a lack of demonstrated relationships might simply reflect limitations of the measures. Similarly, the lack of reliability data on the posttreatment ADIS-IV means that diagnostic criteria may have been assessed less reliably at posttest, and this may have contributed to noise in the data. Significant changes across treatment were demonstrated on all the assessed process variables. It is possible that these changes were due simply to the effects of time because no waiting list control condition was included. However, social phobia is one of the more chronic anxiety disorders (Massion et al., 2002), and waiting list conditions in other studies rarely demonstrate marked changes (e.g., Rapee, Abbott, Baillie, & Gaston, 2007). Therefore, it appears that even broad-based generic treatments are associated with some reduction in factors that maintain social phobia; as a result, the changes in social phobia severity and symptoms associated with all three treatments are not surprising. Importantly, engagement in the enhanced treatment was associated with greater changes on two of the variables the cost of negative evaluation and the perception of personal abilities and attractiveness (negative mental representation) than engagement in the stress treatment and was associated with greater changes on the negative mental representation than engagement in the standard CBT treatment while the difference between these conditions on the cost of negative evaluation approached significance. Of greater interest, the extent to which the enhanced treatment was associated with reductions in the severity of social phobia was mediated by changes in the cost of negative evaluation and the negative mental representation. It is important to point out that data from the mediators and outcome variables were assessed at the same time. Hence, the results cannot indicate a causal relationship, and it remains for future research to determine whether changes in these process variables cause changes in outcome. The findings are consistent with some previous data showing that changes in the perceived cost of negative social events mediate change in social anxiety (Foa et al., 1996; Hofmann, 2004; J. K. Wilson & Rapee, 2005). Although some research has pointed to the importance of a negative mental representation in maintaining social anxiety (Hirsch, Clark, Mathews, & Williams, 2003; Hirsch, Mathews, Clark, Williams, & Morrison, 2006; Rapee & Abbott, 2007) and has demonstrated reductions in this factor following successful treatment (Abbott & Rapee, 2004), mediation of changes in social anxiety through reductions in the negative mental representation has not previously been demonstrated. Importantly, the current results show that the effect of the enhanced program on reducing the perceived cost of negative evaluation and the negative mental representation were associated with key differences between the enhanced treatment and the other treatment packages. Future more tightly con-