Probability and cost estimates for social and physical outcomes in Social Phobia and Panic Disorder

Anxiety Disorders 18 (2004) 481–498

Probability and cost estimates for social and physical outcomes in Social Phobia and Panic Disorder Tanya H. Uren1, Marianna Szabo´*, Peter F. Lovibond School of Psychology, University of New South Wales, Sydney, NSW, Australia Received 19 August 2002; received in revised form 17 October 2002; accepted 16 December 2002

Abstract Individuals with Social Phobia (SP) (n ¼ 23) and Panic Disorder (n ¼ 22), and a nonanxious comparison (NAC) group (n ¼ 62) rated the probability and cost of negative outcomes in the physical and the social domains. Overall, participants rated physical events as less probable but more costly than social events. Compared to the non-anxious group, participants with Social Phobia made significantly higher probability and cost estimates for social events, but not for physical events. Multiple regression analyses demonstrated that perceived cost of negative social events was the strongest unique predictor of scores on the Fear of Negative Evaluation Scale (FNE). Participants with Panic Disorder made significantly higher probability and cost estimates for both physical and social outcomes, compared to non-anxious participants. Both physical probability and social cost estimates predicted scores on the Body Sensations Questionnaire (BSQ). Findings support the disorder-specificity of cognitive biases in Social Phobia, but suggest that individuals with Panic Disorder have a wider range of judgment biases than previously thought. # 2003 Elsevier Science Inc. All rights reserved. Keywords: Social Phobia; Panic Disorder; Cognitive bias; Probability; Cost

*

Corresponding author. E-mail address: [email protected] (M. Szabo´). 1 Present address: Austin & Repatriation Medical Centre, West Heidelberg, Melbourne, Vic., Australia. 0887-6185/$ – see front matter # 2003 Elsevier Science Inc. All rights reserved. doi:10.1016/S0887-6185(03)00028-8

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One of the primary premises of the cognitive approach to anxiety is that anxiety is elicited by an expectation of a harmful or negative event: that is, by a perception of threat (e.g., Beck, Emery, & Greenberg, 1985). Individuals’ perception of threat is thought to be determined by their subjective judgments of the probability of a negative event occurring and the cost or aversiveness of that event (e.g., Carr, 1974). Accordingly, people with anxiety disorders judge the probability and cost of negative events higher, compared to non-anxious controls (Butler & Mathews, 1983; Foa, Franklin, Perry, & Herbert, 1996; Lucock & Salkovskis 1988; McNally & Foa, 1987). Although it is possible that such exaggerated judgments are associated with general levels of clinical impairment or emotional disturbance, several theorists have proposed that they are in fact specific to each anxiety disorder, and likely to play a causal or maintaining role in their development (e.g., Beck et al., 1985; Foa & Kozak, 1985, 1986). For example, individuals with Panic Disorder (American Psychiatric Association (APA), 1994) often believe that symptoms of normal physiological arousal, such as increased heart rate, sweating or dizziness are signs of impending heart attacks or of losing control (e.g., Clark, 1988). In contrast, individuals with Social Phobia (SP) (APA, 1994) are thought to strongly associate social situations (but not symptoms of normal physiological arousal) with an expectation of danger (Foa & Kozak, 1985). According to specificity theories, individuals with these disorders would show differential judgmental biases concerning negative events resulting from physiological symptoms and those resulting from social situations, rather than overestimating the cost and likelihood of all negative events. Most people judge such events as getting a heart attack or losing control as relatively unlikely to occur but highly aversive. In contrast, negative social events, such as embarrassment or rejection, are usually seen as somewhat likely to occur but not very aversive. It has been suggested, therefore, that an overestimation of the probability of arousal-related negative outcomes is most likely to underlie panic, and an overestimation of the cost of negative social events is most likely to underlie social anxiety. According to these suggestions, therapeutic interventions for Panic Disorder would need to focus on reducing exaggerated probability judgments for arousal-related events, while therapeutic interventions for Social Phobia would need to focus on reducing exaggerated cost perception of negative social events (Foa & Kozak, 1985, 1986). Several questions relating to specificity of cognitive biases have been empirically tested using information processing techniques (e.g., Asmundson & Stein, 1994; Hayward, Ahmad, & Wardle, 1994; Hope, Rapee, Heimberg, & Dombeck, 1990) or by examining individuals’ responses to ambiguous scenarios (e.g., Amin, Foa, & Coles, 1998; Clark et al., 1997; Harvey, Richards, Dziadosz, & Swindell, 1993; Zvolensky et al., 2001). Fewer data are available from direct self-report of probability and cost estimates of negative events. Probability and cost judgments are available to consciousness, can be reliably reported, and may be more amenable to therapeutic intervention than are information processing biases

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(McNally, 2001). Furthermore, such judgments are thought to underlie responses to threat (Carr, 1974; Paterson & Neufeld, 1987) and to partly determine the interpretation of ambiguous scenarios (Zvolensky et al., 2001). Therefore, data gained using self-reports of cost and probability estimates have both therapeutic and theoretical implications. In one of the few available studies, McNally and Foa (1987) examined whether agoraphobics would in fact overestimate the cost and probability of arousal-related events, but not of other events, when compared to non-anxious controls. Consistent with the hypotheses, untreated agoraphobics exhibited arousal-specific biases, and a different group of treated agoraphobics showed relatively less bias. Other researchers (Foa et al., 1996; Lucock & Salkovskis, 1988) found support for the specificity hypothesis in Social Phobia. For example, Foa et al. (1996) showed that compared to non-anxious controls, untreated social phobics exaggerated the probability and cost of negative social events, but they did not show such biases concerning non-social events. The biases exhibited by social phobics diminished after treatment. Regression analyses controlling for the interrelationships between the variables showed that a post-treatment reduction of symptom severity was associated with a decrease in cost estimates, rather than in probability estimates, for negative social events. This pattern of results was consistent with the hypotheses that Social Phobia is associated with an overestimation of both the probability and the cost of negative social events, but its association with cost has primary importance. In the studies discussed above (Foa et al., 1996; McNally & Foa, 1987), revised versions of the Subjective Probability and Cost Questionnaire (Butler & Mathews, 1983) were employed to assess judgment biases. The questionnaire used by McNally and Foa (1987) contained arousal-related (e.g., ‘‘You will notice your heart is beating fast’’) and control items, and the version used by Foa et al. (1996) contained social (e.g., ‘‘You will be ignored by someone you know’’) and control items. In both studies, the control items referred to a mixture of nonspecific negative events, for example, ‘‘Your stereo will break down soon’’ or ‘‘You will lose your house keys,’’ as well as some physically threatening events, for example, ‘‘You will get stomach ulcers’’ or ‘‘You will have a minor accident in your car.’’ It is important to note that the questionnaires presented to the Agoraphobic group by McNally and Foa (1987) did not include items referring to social threat, and the questionnaires presented to the Social Phobic group by Foa et al. (1996) did not include items referring to arousal-related threat. Support for the specificity hypothesis of cognitive biases would be strengthened by showing that particular biases differentiate between anxiety disorders. In other words, it is important to assess clinically anxious individuals’ probability and cost biases concerning events that, according to the specificity theory, should not pose heightened threat to them, but should pose heightened threat to individuals with a different anxiety disorder. While some evidence for such disorder-specificity is available from

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information processing studies (Hope et al., 1990), no data on probability and cost judgments are presently available. Further, the strategy of item selection in the previous studies (Foa et al., 1996; McNally & Foa, 1987), while appropriate for their purposes, may have resulted in questionnaires with limited external validity. The control items often refer to minor events that may not be associated with any well-defined fears, either in normal or in clinical populations. The evidence in support of the specificity theory would be strengthened if it could be shown that both the disorder-specific and the non-disorder-specific items reflect events that are representative of feared negative outcomes in the population. Accordingly, the present study aimed to clarify and extend previous research in several ways. First, we expanded and refined the item content of the Subjective Probability and Cost Questionnaire on the basis of research investigating the structure of feared outcomes in long-term memory in the general population. This research has consistently identified two higher-order factors, interpreted as referring to ‘‘negative social evaluation,’’ for example, embarrassment, humiliation or rejection, and to ‘‘physical harm,’’ for example, death, illness, accidents, or financial difficulties (Eysenck & Van Berkum, 1992; Lovibond & Rapee, 1993; Stattin, Magnusson, Olah, Kassin, & Reddy, 1991). Therefore, we included items that are representative of the social and physical threat domains. This strategy also enabled us to test whether agoraphobics’ cost and probability biases are in fact specific to arousal-related events (McNally & Foa, 1987), or, alternatively, whether they include other types of physical events as well, as previously indicated by information processing studies (Asmundson, Sandler, Wilson, & Walker, 1992; Hope et al., 1990). To investigate the specificity of cognitive biases between diagnostic groups, we included both a Panic/Agoraphobic and a Social Phobic group in the study, and asked the participants to estimate the probability and cost of both physical and social events. By selecting items that reflect a range of feared outcomes reported in the general population, and including both Panic/Agoraphobic and Social Phobic groups, we were able to test the proposition that pathological social anxiety is most strongly associated with an overestimation of the subjective cost of social events, while Panic/Agoraphobia is most strongly associated with an overestimation of the subjective probability of arousal-related events. Our main hypotheses were as follows. First, in general, participants were expected to rate the probability of social events higher than the probability of physical events, and to rate the cost of physical events higher than the cost of social events. Second, clinic-referred anxious participants in general were expected to rate both the probability and cost of negative social and physical events higher, compared to non-anxious participants. Finally, we expected that individuals with Panic Disorder would estimate the cost and probability of physical outcomes as higher compared to individuals with Social Phobia, whereas individuals with Social Phobia would estimate the probability and cost of social

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outcomes as higher. This effect was expected to be especially pronounced for the probability of physical outcomes and the cost of social outcomes.

1. Method 1.1. Participants 1.1.1. Clinical samples The two clinical samples comprised participants who met DSM-IV criteria (APA, 1994) for either Social Phobia (n ¼ 23) or Panic Disorder (n ¼ 22). Twenty participants in the Panic Disorder group met DSM-IV criteria for Panic Disorder with Agoraphobia (PANAG). Therefore, this group will be referred to as the PANAG group. The two groups of clinically anxious participants were recruited from specialized anxiety disorder clinics, where they were awaiting treatment for either Social Phobia or Panic Disorder. Individuals with a history of disorders that would interfere with their response to group treatment (e.g., borderline personality disorder or psychosis) were referred to more appropriate treatment specialists at their intake interview, and were therefore excluded from the study. Inclusion criteria were ages between 16 and 65 years, a proficiency in English, and a primary diagnosis of Social Phobia or Panic Disorder. Diagnoses of Social Phobia and Panic Disorder were established using either the Composite International Diagnostic Interview (CIDI) version 2.1 (World Health Organization, 1997) or the Anxiety Disorders Interview Schedule-Revised (ADIS-R; DiNardo & Barlow, 1994). Several of the participants met criteria for more than one disorder. Group allocation for these participants was made on the basis of their primary diagnosis, determined in all instances by an experienced clinical psychologist with postgraduate training. Because of ethical considerations at some of the clinics we approached, we had access to detailed information on comorbid conditions for only a subset of the clinic-referred participants (8 participants in the SP group and 11 participants in the PANAG group). The majority of these participants received comorbid diagnoses of Generalized Anxiety Disorder (six in the SP group and six in the PANAG group). To assess and statistically control for comorbid social anxiety and panic symptomatology, we used self-report questionnaires, as detailed in the Materials section. 1.1.2. Non-clinical sample The community sample comprised 101 volunteers (61 females, 40 males) recruited with the aim of obtaining a sample representing a wide range in age, socio-economic background, and level of education. The mean age of the community sample was 39.89 (S:D: ¼ 12:14). To maximize the power for correlation analyses, a range of scores on the dimensional measures utilized in the study was deemed desirable. Therefore, there were no formal exclusion

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criteria imposed on participant selection in the community sample. However, for the between-group analyses a non-anxious comparison (NAC) group was drawn from the community sample. Participants who scored within the clinical range on anxiety and depression symptom measures were excluded from selection into the NAC group. This strategy yielded a NAC sample comprising 62 participants. The mean age of the NAC, Social Phobia and PANAG groups was 41.03 (S:D: ¼ 12:2), 34.64 (S:D: ¼ 10:84), and 37.82 (S:D: ¼ 11:3) years, respectively. The difference in mean age between the NAC and combined clinical groups just reached significance (tð104Þ ¼ 2:08, P < :05). Percentage of female participants was 59.7 in the NAC group, 60.9 in the SP group, and 77.3 in the PANAG group (w2 ð1Þ ¼ 1:3, P > :05). 1.2. Measures 1.2.1. Diagnostic interviews The participating specialist anxiety clinics used either the Composite International Diagnostic Interview version 2.1 (World Health Organization, 1997) or the Anxiety Disorders Interview Schedule-Revised (DiNardo & Barlow, 1994), as a part of their routine intake assessments. Both the CIDI and the ADIS-R have excellent reliability and validity (Andrews & Peters, 1998; DiNardo & Barlow, 1994). Thirty-six percent of the clinically anxious participants were diagnosed using the CIDI. Clinical psychologists with postgraduate training carried out all diagnostic assessments. 1.2.2. Anxiety and depression symptoms We used the Fear of Negative Evaluation Scale (FNE; Watson & Friend, 1969) and the Body Sensations Questionnaire (BSQ; Chambless, Caputo, Bright, & Gallagher, 1984) to assess social anxiety and panic symptoms, respectively. The Fear of Negative Evaluation Scale (Watson & Friend, 1969) is a 30-item scale requiring true or false responses. It was designed to assess expectations and apprehension concerning anticipated negative evaluations by others. The FNE is considered to be sensitive to social anxiety and its test–retest reliability is adequate (r ¼ :78; Turner, McCanna, & Beidel, 1987). Although this measure has previously been found to have low levels of specificity to Social Phobia as defined in DSM (Turner et al., 1987), the use of the FNE allowed us to assess and control for symptoms of social anxiety that are associated with a wide range of anxiety disorders, in addition to Social Phobia (Heimberg, Hope, Rapee, & Bruch, 1988). The item content of the Body Sensations Questionnaire (Chambless et al., 1984) was derived from distressing bodily symptoms reported by agoraphobic clients. It contains 18 items that are rated on a five-point Likert scale from 1 (‘‘not frightened’’) to 5 (‘‘extremely frightened’’). The scale has been found to be internally consistent (Cronbach a ¼ 0:87) and its test–retest reliability over 31 days is moderate (r ¼ :67; Chambless et al., 1984).

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The Depression Anxiety Stress Scales (DASS; Lovibond & Lovibond, 1995b) was designed to differentiate between the three syndromes of negative affect: depression, anxiety and stress. It utilizes a four-point Likert scale between 0 (‘‘did not apply to me’’) and 3 (‘‘applied to me very much’’). The seven-item Depression and Anxiety scales from the short version of the DASS were used. The DASS scales have high internal consistency, as well as good convergent and discriminant validity, both in clinical and in non-clinical samples (Antony, Bieling, Cox, Enns, & Swinson, 1998; Lovibond & Lovibond, 1995a, 1995b). In accordance with published norms (Chambless et al., 1984; Lovibond & Lovibond, 1995a, 1995b; Turner et al., 1987), individuals who scored below 19 on the Fear of Negative Evaluation Scale, 59 on the Body Sensations Questionnaire, 13 on DASS Depression and 9 on DASS Anxiety were included in the nonanxious comparison group. 1.2.3. Outcome Probability and cost estimates The Outcome Probability Questionnaire (OPQ) and the Outcome Cost Questionnaire (OCQ) were derived from an expanded set of items employed by Butler and Mathews (1983), Foa et al. (1996), and McNally and Foa (1987). The OPQ and the OCQ consist of the same 24 items, describing possible negative outcomes of varying severity. Based on Lovibond and Rapee’s (1993) factor analytic study of feared outcomes in the general population, 12 items target physical threat (e.g., ‘‘You will have a heart attack or stroke’’), and 12 items target social threat (e.g., ‘‘You will feel embarrassed by something you did’’). This item content was subsequently refined by factor analyses, as discussed in Section 2. The OPQ requires participants to rate how likely it is that the social and physical negative outcomes will happen to them in the next year. The OCQ asks participants to rate how bad or distressing the same outcomes would be for them if they were to occur. As in previous research, nine-point Likert-type scales ranging from 0 (‘‘not at all’’) to 8 (‘‘extremely’’) were used for the ratings. 1.3. Procedure Individuals in the community group were approached by the first author at their places of employment or education and asked to take part in a study about judgments about different events. The return of the completed anonymous questionnaire battery was taken to assume informed consent. Clinic-referred participants were asked whether they were interested to take part in the study either by the first author or by the clinician conducting their intake interview. They completed the questionnaires during or shortly after their intake assessment. Wherever possible, these participants completed the same battery of symptom measures that the community sample received. However, to reduce demands on the clients, one of the anxiety clinics administered only the OPQ and OCQ, omitting the anxiety and depression symptom measures.

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2. Results 2.1. Psychometric properties of the OPQ and the OCQ A principal axis factor analysis with oblique rotation specifying two factors was carried out separately on the Outcome Probability Questionnaire and the Outcome Cost Questionnaire. This procedure identifies the latent constructs that explain the pattern of intercorrelations among a set of items (see Fabrigar, Wegener, MacCallum, & Strahan, 1999). Results of the factor analyses are shown in Table 1.

Table 1 Factor analysis of the Outcome Probability Questionnaire and the Outcome Cost Questionnaire across both social and physical domainsa OPQ factor

OCQ factor

1

1

Social items You will feel embarrassed by something you did .83 You will sound dumb while talking to others .83 You will feel flustered in front of others .77 People will think you are boring .74 At a party, others will notice that you are nervous .68 During a job interview or evaluation, you will freeze .64 While you are talking with several people, one of .64 them will leave You will be ignored by someone you know .64 You will do something foolish in public .56 You will fail to accomplish an important goal .52 You will fail to cope in your day-to-day living .42 You will be unexpectedly called in to see your supervisor at work Physical items You will have a heart attack or stroke You will need to have a major surgical operation A burglar will break into your home while you are away You will faint in public You will be mugged, but not seriously hurt Someone close to you will be diagnosed with a terminal illness You will be audited by the taxation department You will lose your purse or wallet You will go crazy You will have a minor accident in your car You will get a disease from using a public toilet You will find that you are overdrawn a lot on your bank account a

Loadings below .30 are not shown.

2

2

.85 .85 .80 .71 .79 .57 .81 .80 .85 .38 .55

.36 .60

.82 .77 .72 .71 .71 .59 .50 .49 .44 .42 .38 .32

.78 .73 .57 .40 .70 .73 .40 .50 .67 .42 .58 .51

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The two factors accounted for 47.46% of the total variance on the OPQ, and for 53.79% of the total variance on the OCQ. The correlation between Factor 1 and Factor 2 was .46 on the OPQ and .52 on the OCQ. For both the Outcome Probability and the Outcome Cost Questionnaires, most of the social items loaded on one factor (Factor 1) and most of the physical items loaded on the other factor, as expected. The factor loadings were used to refine the social and physical scales. A minimum loading of .30 was chosen as the criterion in assigning items to a factor. This strategy resulted in the first 10 social and the first 10 physical items in Table 1 being retained. For example, the social item ‘‘you will fail to cope in your day-to-day living’’ loaded on both Factors 1 and 2 on the Outcome Probability Questionnaire; and loaded on Factor 2 only on the Outcome Cost Questionnaire, and was consequently dropped. Both the OPQ and the OCQ demonstrated high internal consistency. Cronbach alphas for the 20-item OPQ and OCQ were as follows: OPQ total a ¼ 0:90, OCQ total a ¼ 0:92, OPQ social a ¼ 0:89, OPQ physical a ¼ 0:87, OCQ social a ¼ 0:94, OCQ physical a ¼ 0:86. Pearson correlation coefficients were calculated to examine the relationship between social probability, social cost, physical probability and physical cost ratings. Probability and cost estimates of social outcomes were positively correlated (r ¼ :64, P < :05). In contrast, the correlation between probability and cost estimates of physical outcomes did not reach significance (r ¼ :14, P > :05). Correlations between physical probability and social cost (r ¼ :34, P < :05) and social probability and physical cost (r ¼ :28, P < :05) were low but statistically significant. This pattern of results is similar to that reported previously (e.g., Foa et al., 1996). 2.2. Anxiety and depression symptom measures Table 2 shows the average scores obtained on symptom measures of anxiety and depression by the NAC, SP and PANAG groups. Group-based data analyses were conducted via a set of planned, orthogonal contrasts, controlling the decision-wise error rate at 0.05. One contrast compared the non-clinical group to the combined clinical groups, and the other contrast compared the Social Phobic group with the PANAG group. Table 2 Mean scores (and standard deviations) for non-anxious comparison, Social Phobia and Panic Disorder/Agoraphobia groups on anxiety and depression symptom measures

BSQ FNE DASS Depression DASS Anxiety

Non-anxious

Social Phobia

Panic Disorder

N

30.81 7.13 4.03 1.90

39.56 26.14 17.36 14.18

59.06 19.41 19.71 22.14

97 100 105 105

(8.75) (5.31) (3.25) (2.16)

(14.24) (3.62) (10.77) (10.56)

(9.38) (9.54) (12.86) (12.47)

BSQ: Body Sensations Questionnaire; FNE: Fear of Negative Evaluation Scale; DASS: Depression Anxiety Stress Scales.

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Planned orthogonal contrasts indicated that the scores of the two clinically anxious groups were elevated on each measure, compared to non-anxious controls (Fð1; 97Þ ¼ 161:75 for FNE, Fð1; 94Þ ¼ 75:50 for BSQ, F’sð1; 102Þ ¼ 119:33 for DASS Anxiety and 85.30 for DASS Depression, all P’s < :05). The diagnostically specific measures differentiated between the two clinical groups; individuals with Social Phobia scored higher on the FNE (Fð1; 97Þ ¼ 12:02, P < :05), and individuals with PANAG scored higher on the BSQ (Fð1; 94Þ ¼ 32:81, P < :05). Further, although the two clinically anxious groups did not differ from each other in their level of DASS Depression (Fð1; 102Þ ¼ 0:95, NS), the PANAG group scored higher than the Social Phobia group on DASS Anxiety (Fð1; 102Þ ¼ 12:11, P < :05). This latter finding may reflect an emphasis on autonomic arousal symptoms in the DASS Anxiety scale. 2.3. Probability and cost estimates As in the case of symptom measures, we carried out group-based comparisons concerning probability and cost judgments using a set of planned, orthogonal contrasts (Bird, Hadzi-Pavlovic, & Isaac, 2000). In addition to hypothesis tests, 95% standardized Confidence Interval (CI) limits were also calculated (Bird, 2002) to provide maximum information about effect sizes in our main results. Probability and cost estimates were analyzed separately. 2.3.1. Probability estimates for physical and social outcomes Fig. 1 graphically represents the probability estimates given for negative social and physical events by the three groups. In accordance with expectations, social outcomes were rated by the participants as more likely to occur than physical outcomes (overall M’s ¼ 33:49 and 16.33, S:D:’s ¼ 15:12 and 11.42 for social and physical events, respectively, Fð1; 104Þ ¼ 134:72, P < :05, 95% CI for effect size: 1.06, 1.50). Further, averaged over Outcome Type, non-anxious participants gave lower probability estimates than did the two clinical groups (M’s ¼ 16:86 and 28.94, S:D:’s ¼ 8:50 and 14.62 for NAC and clinic groups, respectively, Fð1; 104Þ ¼ 28:68, P < :05; 95% CI for effect size: 1.24, 0.57). The two clinic-based groups did not differ from each other (M’s ¼ 28:15 and 29.73, S:D:’s ¼ 11:02 and 17.87 for SP and PANAG, respectively, Fð1; 104Þ ¼ 0:21, NS; 95% CI for effect size: 0.63, 0.39). These main effects were qualified by significant interactions between groups and Outcome Type. Social probability ratings differentiated the clinical groups from the NAC group better than did physical probability ratings (Fð1; 104Þ ¼ 11:48, P < :05, 95% CI for effect size: 0.28, 1.08). The difference between the Social Phobic and PANAG groups also varied according to Outcome Type (Fð1; 104Þ ¼ 24:08, P < :05, 95% CI for effect size: 2.10, 0.89). As Fig. 1 suggests, the PANAG group rated the probability of physical outcomes higher than did the Social Phobia group, while social phobics appeared to rate the probability of social outcomes higher, compared to the PANAG group. However,

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Fig. 1. Probability estimates given for negative social and physical events by the Social Phobic, Panic/Agoraphobic, and non-anxious comparison groups.

simple effects analyses showed that although the PANAG group estimated the probability of physical outcomes significantly higher than did the SP group (Fð1; 104Þ ¼ 11:59, P < :05; 95% CI for effect size: 0.36, 1.37), the difference between the PANAG and SP groups on social probability judgments only approached statistical significance (Fð1; 104Þ ¼ 3:51, P ¼ :06; 95% CI for effect size: 1.30, 0.04). 2.3.2. Cost estimates for physical and social outcomes Fig. 2 shows the cost ratings given for social and physical outcomes by the three groups. Overall, the participants rated the cost of physical outcomes higher, compared to the cost of social outcomes (M’s ¼ 55:44 and 39.67, S:D:’s ¼ 13:92 and 14.11, respectively, Fð1; 104Þ ¼ 119:65, P < :05; 95% CI for effect size: 0.92, 1.33). Averaged over Outcome Type, the NACs rated the cost of negative events lower than did the clinical groups (M’s ¼ 37:02 and 47.99, respectively, Fð1; 104Þ ¼ 42:81, P < :05; 95% CI for effect size: 1.47, 0.79), who did not differ from each other (Fð1; 104Þ ¼ 0:76, NS; 95% CI for effect size: 0.79, 0.30). Again, these main effects were qualified by interactions between group and Outcome Type. Social cost ratings differentiated the clinical groups from the NAC group better than did physical cost ratings (Fð1; 104Þ ¼ 48:90, P < :05; 95% CI

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Fig. 2. Cost estimates given for negative social and physical events by the Social Phobic, Panic/ Agoraphobic, and non-anxious comparison groups.

for effect size: 0.93, 1.67). The size of the difference between the two clinical groups again varied according to Outcome Type (Fð1; 104Þ ¼ 10:54, P < :05; 95% CI for effect size: 1.48, 0.40). As in the case of probability estimates, simple effects analyses showed that compared to the Social Phobic group, the PANAG group rated the cost of physical outcomes higher (Fð1; 104Þ ¼ 5:43, P < :05; 95% CI for effect size: 1.28, 0.10), but that there was no difference between the Social Phobic and PANAG groups in their ratings of the cost of social outcomes (Fð1; 104Þ ¼ 0:59, NS; 95% CI for effect size: 0.36, 0.83). To explore whether the results concerning physical outcomes were primarily driven by the items reflecting physiological arousal, each of the analyses was repeated, with a revised version of the Outcome Probability and Cost Questionnaires. In the revised version, items reflecting physiological arousal were omitted from the physical outcomes scales, and only the items reflecting general physical threat were retained. The analyses involving the revised scales replicated the pattern of results reported above. 2.4. Dimensional analyses To control for the associations between probability and cost judgments, as well as between social phobic and panic symptoms (Brown & Barlow, 1992),

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Table 3 Pearson correlation coefficients between anxiety symptoms measures and cost and probability judgments

BSQ Social probability Social cost Physical probability Physical cost

FNE

BSQ

.41 .56 .71 .07 .28

.25 .49 .23 .33

BSQ: Body Sensations Questionnaire; FNE: Fear of Negative Evaluation Scale.

simultaneous multiple regression analyses were carried out, entering all predictor variables into the equation in one step (Cohen & Cohen, 1983). For these analyses, data from the full sample including the two clinical samples and the community sample were used (N ¼ 146). The Fear of Negative Evaluation Scale and the Body Sensations Questionnaire were employed to assess socially phobic and panic symptomatology, respectively. The intercorrelations among these variables are presented in Table 3. In the first regression analysis, FNE scores were entered as the criterion variable, the four probability and cost estimates were entered simultaneously as the predictors, and the BSQ was also simultaneously entered as a predictor to control for comorbid PANAG symptomatology. The model containing all five variables explained 57.4% of the variance in FNE scores (Fð5; 129Þ ¼ 34:73, P < :001). Social cost judgments were found to be the strongest predictor of FNE scores (b ¼ 0:56; t ¼ 6:32, P < :001), while social probability judgments also added to the prediction (b ¼ 0:31; t ¼ 4:02, P < :001). Interestingly, physical probability judgments (b ¼ 0:23; t ¼ 3:49, P < :01) received a significant negative regression weight. In the second regression analysis, the four probability and cost estimates were simultaneously entered to predict scores on the BSQ, with FNE scores also entered as a predictor to control for comorbid SP symptomatology. The full model explained 29.2% of the variance in BSQ scores (Fð5; 129Þ ¼ 10:62, P < :001). Social cost (b ¼ 0:29; t ¼ 2:24, P < :05) and physical probability (b ¼ 0:20; t ¼ 2:35, P < :05) were both found to be significant independent predictors of BSQ. These regression analyses were repeated controlling for age (that is, we entered age simultaneously together with the other predictors) and the same pattern of results was obtained.

3. Discussion This study examined the differential pattern of probability and cost judgments for negative events in individuals with Social Phobia and Panic Disorder, and in a

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non-anxious comparison group. We explored whether predictions derived from specificity theories of cognitive biases in anxiety disorders (e.g., Foa & Kozak, 1985, 1986) would be supported by the data when a wide range of outcomes within two well-defined domains are presented to the participants. These two domains were previously identified in the general population, and represent social and physical outcomes (Lovibond & Rapee, 1993). The data obtained from the factor analyses in our study offer support for the social/physical dichotomy of feared outcomes. The two-factor solution yielded a clear separation of the items into those referring to social threat and those referring to physical threat, with few items failing to load clearly on one of the two factors. The distinction between social and physical concerns was also evident in the correlational analyses; probability and cost estimates of social outcomes were moderately correlated, whereas the correlation between probability and cost estimates of physical outcomes did not reach significance. These findings are consistent with the data reported by Foa et al. (1996), who found a strong positive relationship between the probability and cost of social outcomes, but no significant correlation between the probability and cost of mixed non-social outcomes. Unlike previous studies (Foa et al., 1996; McNally & Foa, 1987), we chose items that represent a wide range of feared outcomes, and did not attempt to equate the social and physical scales in terms of their probability and cost. By employing this strategy, we aimed to achieve a more ecologically relevant set of items. Accordingly, we expected that participants would rate the likelihood of social events higher than the likelihood of physical events, but they would estimate the cost of physical events higher than the cost of social events (Foa & Kozak, 1986). The data supported both predictions. So, although the psychometric properties of the questionnaires containing our lists of stimuli are yet to be fully established, our initial analyses support their construct validity. In the main analyses we tested several hypotheses aiming to assess the disorder-specificity of judgment biases (e.g., Foa & Kozak, 1985, 1986). In general, the results concerning the nature of cognitive biases in Social Phobia were more consistent with these predictions than were the results concerning Panic Disorder/Agoraphobia. We found that individuals with Social Phobia differed from non-anxious controls in that they overestimated the probability and cost of negative social events, but they did not overestimate the probability and cost of physical events. In fact, social phobics estimated the cost of negative social outcomes to be nearly as high as the cost of negative physical outcomes. This finding is especially noteworthy in light of the wide range of outcomes reflected in the ‘‘Physical’’ scale, which included such items as ‘‘having a heart attack’’ or ‘‘going crazy.’’ The importance of social cost judgment biases in social anxiety was further underlined by the results of the regression analyses. Controlling for the overlap between probability and cost judgments and for the comorbidity of panic and social anxiety symptoms, the results confirmed that social cost judgments are the most important predictors of social anxiety, as measured by the FNE.

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Results concerning the nature of cognitive biases in Panic Disorder/Agoraphobia are less clear. First, individuals with PANAG were found to overestimate the probability and cost of negative physical events compared to the Social Phobic group, as well as to the non-anxious comparison group. The physical items used in this study involved some outcomes known to be feared by individuals with PANAG (e.g., having a heart attack), but also included a wide range of negative outcomes not related to physiological arousal (e.g., having a car accident). Our analyses involving only the non-arousal-related items replicated the results involving the whole scale. These results suggest that PANAG participants’ cognitive biases in the physical domain are not restricted to stimuli associated with physiological arousal, but include a wide range of physically threatening events, as shown in previous studies using information processing strategies (e.g., Asmundson et al., 1992; Hayward et al., 1994). Further, there were no differences between the two clinical groups in their judgments concerning social events. Both the Social Phobic and the PANAG groups overestimated the probability and the cost of negative social outcomes, compared to non-anxious participants. These data suggest that cognitive biases in individuals with Panic Disorder are not restricted to physical outcomes, but that they spread across a range of physical and social outcomes. It is difficult to determine to what extent this finding is attributable to comorbid Social Phobia in the Panic Disorder group, or to their possibly higher general distress, rather than having any specific implication for their disorder. The Fear of Negative Evaluation Scale (Watson & Friend, 1969) was used in this study as a dimensional measure of Social Phobic symptoms. Although the Panic Disorder group had higher FNE scores than did the non-anxious control group, their scores were significantly lower than those of the Social Phobia group. This pattern was not mirrored by the group differences in cost and likelihood appraisal for social outcomes, making it unlikely that the Panic Disorder participants’ cognitive biases reflected comorbid social anxiety. Results of the regression analysis were also inconsistent with such a possibility. Although physical probability judgments were found to be strong independent predictors of panic symptoms, social cost judgments played a similarly important role. Because comorbid symptoms of social anxiety were statistically controlled for, these could not have caused the present pattern of results. The greater pervasiveness of outcome concerns in the Panic Disorder group may also be attributable to a higher anxiety in these participants, as indicated by their elevated DASS Anxiety scores, compared to both the non-anxious and the Social Phobic groups. However, increased DASS Anxiety scores are typically associated with increased physical concerns, rather than increased social concerns (Lovibond & Rapee, 1993), making it unlikely that the Panic Disorder group’s cognitive biases concerning social events were related to their increased anxiety. Collectively, the data do not support the notion that the relatively wider range of cognitive biases in the Panic Disorder group was attributable to their possible comorbid Social Phobia or to their relatively higher anxiety level.

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3.1. Conclusions and suggestions for further research The current study has some important theoretical and therapeutic implications. At the most general level, the data document the presence of the social/ physical dichotomy (Lovibond & Rapee, 1993) in individuals’ conscious appraisals of probability and cost, and reinforce the notion that cognitive biases concerning such appraisals may play a role in the maintenance of anxiety disorders (Foa & Kozak, 1985). The finding that individuals with Social Phobia only have social threat biases but not physical threat biases, and that their biases concerning the cost of negative social events are especially strong, appear to be robust (Foa et al., 1996; Lucock & Salkovskis, 1988). Results showing that PANAG participants overestimated the probability and cost of physical threat provide evidence that cognitive bias in Panic Disorder is not specific to arousalrelated outcomes. Furthermore, PANAG participants also evidenced exaggerated social threat appraisals. These results suggest that focusing on the domain of physiological arousal in therapy may not be sufficient for the effective treatment of Panic Disorder, and are in accordance with recent theories emphasizing the importance of social fears in the development of agoraphobic avoidance (e.g., Salkovskis & Hackman, 1997). Because this study employed a cross-sectional and correlational design, conclusions about causation can not yet be drawn. Building on the present results, future experimental or prospective studies involving alternative, multi-method assessment techniques may greatly enhance our understanding of the relationships between specific cognitive biases and anxiety disorders.

Acknowledgments The authors would like to thank Danielle Einstein at Westmead Hospital Anxiety Management Clinic, Jonathan Gaston at Macquarie University Anxiety Research Unit, and Dr. Renate Wagner at Bankstown Hospital Anxiety Clinic for their assistance with this project, and those who kindly volunteered to participate in the study. The data were collected as a part of the research requirements for a Master of Science degree for Tanya H. Uren.

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