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Evaluating anxiety sensitivity and other fundamental sensitivities predicting anxiety symptoms and fearful responding to a biological challenge
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Behaviour Research and Therapy 44 (2006) 1681–1688 www.elsevier.com/locate/brat
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Evaluating anxiety sensitivity and other fundamental sensitivities predicting anxiety symptoms and fearful responding to a biological challenge Norman B. Schmidt, Michael Mallott Department of Psychology, Florida State University, Tallahassee, FL 32306, USA Received 13 July 2005; received in revised form 30 November 2005; accepted 6 December 2005
Abstract Fear of arousal symptoms, often referred to as anxiety sensitivity (AS), appears to be associated with risk for anxiety pathology and other Axis I conditions. However, AS is only one of three fundamental components of Reiss’ Expectancy Model proposed to account for the development of anxiety problems. Very little research has focused on the other two components of this model (Fear of Negative Evaluation, Illness/Injury Sensitivity) and the specificity of AS, relative to these other two components, has rarely been evaluated. This study evaluated general and unique associations among all three so-called fundamental sensitivities to fearful responding to a biological challenge in a nonclinical sample (N ¼ 404). Participants were administered a 20-s inhalation of 20% CO2/balance O2. Consistent with hypothesis, only AS uniquely contributed to increased subjective fear responding to the challenge. These findings are consistent with Expectancy Theory in suggesting that the AS component of the model is specific to amplification of fears to arousal cues. r 2005 Elsevier Ltd. All rights reserved. Keywords: Anxiety; Risk factor; Vulnerability; Anxiety disorder
Introduction Converging lines of evidence suggest that anxiety disorders in adulthood may represent manifestations of an underlying constitutional vulnerability or diathesis for anxiety that is partly genetic and variably expressed over the life cycle. An individual’s overall risk for pathology is believed to be a function of personal genetic and nongenetic resiliency and vulnerability factors, environmental risk and protective factors, and interactions among these factors. In terms of nongenetic risks, perhaps one of the best researched psychological risk factors for anxiety is a construct called anxiety sensitivity (AS). AS refers to the extent to which an individual believes that symptoms of anxiety or arousal can have harmful consequences (Reiss & McNally, 1985). A growing body of AS research has focused on establishing this variable as a vulnerability factor in the development of anxiety pathology. Accumulating findings from laboratory (Rapee & Medoro, 1994) and prospective Corresponding author. Tel.: +1 850 644 1707; fax: +1 850 644 7739.
E-mail address: [email protected] (N.B. Schmidt). 0005-7967/$ - see front matter r 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.brat.2005.12.001
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(Schmidt, Lerew, & Jackson, 1997, 1999) studies have provided converging evidence that AS acts as a specific risk factor in the development of anxiety pathology (see Taylor, 1999, for a review). It is notable, however, that AS is only one of three cognitive risk factors posited by Expectancy theory (Reiss & McNally, 1985). Expectancy theory proposed that anxiety problems such as panic attacks and phobias arise from three fundamental sensitivities: (1) AS, (2) fear of negative evaluation, and (3) injury/illness sensitivity. Fear of negative evaluation refers to concerns and fear regarding negative evaluation from others and illness/injury sensitivity is described as fear of injury and illness. Reiss (1991) describes these dimensions as fundamental in the sense that they represent the potential to fear inherently aversive stimuli or events (e.g., humiliation, death). In addition, other common fear reactions or pathologies are believed result from these fundamental sensitivities. For example, fear of aversive bodily perturbations may result in the development of panic attacks or panic disorder. Fear of negative evaluation may result in social anxiety disorder and fear of injury/illness may contribute to the development of generalized anxiety disorder. Despite considerable research on AS, there is very little empirical work on the other two dimensions of Expectancy theory. Some early work suggested that these fundamental dimensions are factorially distinct (Reiss, Peterson, & Gursky, 1988). The distinctiveness of Expectancy factors was later confirmed by Taylor (1993). There are also a handful of studies suggesting that different Expectancy dimensions may be related to phobias and fears (Gursky & Reiss, 1987; McNally & Louro, 1992). For example, in one of the most comprehensive analyses of the relationship among these dimensions and anxiety symptoms, Taylor (1993) found that one or more of the Expectancy dimensions were related to trait anxiety, social fears, phobic avoidance, animal fears and blood injury fears. Despite these initial promising findings, there are virtually no studies of fear of negative evaluation or injury sensitivity since Taylor’s study in the early 1990s. The main aim of the present study is to provide an evaluation of the three dimensions of Expectancy theory in the context of fearful responding to a biological challenge. There is some literature that has evaluated the specificity of AS in terms of biological challenges (see Zvolensky & Eifert, 2001 for a review). For example, AS has been found to be predictive of fearful responding to challenge even after controlling for other relevant diagnostic (Schmidt, Trakowski, & Staab, 1997) psychological (Zvolensky, Feldner, Eifert, & Stewart, 2001) and genetic factors (Schmidt et al., 2000). In the present report, we were interested in testing the discriminant properties of AS, relative to the other dimensions of Expectancy theory, in the context of fearful responding to a biological challenge. Consistent with prior work, we expected that AS would be uniquely associated with challenge-induced panic symptoms and anxiety. Method Participants Participants took part in a longitudinal, primary prevention study (see Schmidt et al., 2005 for additional details). Exclusion criteria for this study include age restrictions (i.e., age range ¼ 14–25) and the presence of any current Axis I diagnosis. Participants were recruited from the Columbus, OH metropolitan area school system (n ¼ 46), the Ohio State University (n ¼ 263), and the Columbus, OH community (n ¼ 96). The sample was relatively young (age M ¼ 19.3, SD ¼ 3.9) with the majority being female (61%). The sample was also primarily white (74%) with 10% African-American, 9% Asian-American, 2% Hispanic, and 3% Other. Completion of college was the most frequently endorsed level of parental education with 30% of mothers and 29% of fathers finishing college. Assessments A multi-modal assessment battery was administered to all participants. This battery consisted of clinicianrated measures as well as self-rated measures. In addition, participants completed a 20% CO2 challenge. Diagnostic interview Psychiatric diagnoses were made using structured diagnostic interviews (SCID-IP; First, Spitzer, Gibbon, & Williams, 1994). Interviews were conducted by advanced graduate students in clinical psychology who had
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received extensive training in SCID administration and scoring. This training included reviewing SCID training tapes, observing taped SCID administration, observing live SCID administration, and conducting SCID interviews with a trained interviewer. Interviewers received feedback throughout this process until they demonstrated high reliability. These same training procedures have been used in other projects in our laboratory that have generated high inter-rater reliability for all Axis I diagnoses (Schmidt, Staab, Trakowski, & Sammons, 1997). A consensus method of diagnosis was used at weekly staff meetings where positive diagnostic findings were reviewed. The typical inter-rater reliability evaluation was not conducted due to participant selection criteria at baseline (i.e., absence of Axis I pathology). Self-report measures Dependent variables. Acute Panic Inventory (API). The API is a 17-item inventory for assessing symptoms of arousal associated with panic attacks (Liebowitz, Gorman, Fyer, Dillon, & Klein, 1984). The API has been used extensively in panic provocation studies (Fyer, Uy, Martinez, & Goetz, 1987; Gorman et al., 1994; Harrison et al., 1989; Schmidt, Eggleston, Trakowski, & Smith, in press). Participants rate the severity of each symptom from 0 (absent) to 3 (severe). The API includes a SUDS rating of self-reported anxiety (0—no anxiety, 100—extreme anxiety). Predictor variables—expectancy dimensions. The three expectancy dimensions were operationalized using three self-report measures. As is commonly done, the Anxiety Sensitivity Inventory (ASI) (Reiss, Peterson, Gursky, & McNally, 1986) was used to measure AS. Similar to the Taylor (1993) report, the brief Fear of Negative Evaluation scale (Leary, 1983) was used to measure Fear of Negative Evaluation and the Injury Sensitivity Index (Taylor, 1993) was used to measure Illness/Injury Sensitivity. Unlike the Taylor study, which conducted a factor analysis of items from each of these scales and used the resulting factors for analyses, we simply used the scales for a number of reasons including: (1) for ease of interpretability, (2) Taylor’s factor analysis found that the scales largely cohered with the exception of some of the social items from the ASI loading on the Fear of Negative Evaluation factor, and (3) in the present study, factor analytically derived subscales yielded a pattern of findings comparable to those reported with the original scales. ASI. The ASI (Reiss et al., 1986) is a 16 item self-report measure of the fear of bodily sensations associated with arousal. Each item consists of a possible negative consequence of anxiety symptoms. The structure of the ASI is hierarchical and consists of three first-order factors (i.e., AS-physical concerns, AS-mental incapacitation concerns, and AS-social concerns) (Zinbarg, Barlow, & Brown, 1997). The factor structure and psychometric properties of the ASI have been replicated across diverse populations, testifying to its broad-based applicability (Carter, Miller, Sbrocco, Suchday, & Lewis, 1999; Schmidt & Joiner, 2002; Zvolensky, McNeil, Porter, & Stewart, 2001). The scale showed good internal consistency in the present sample (a ¼ :87). Fear of negative evaluation (FNE). The FNE is a popular measure of expectation and distress related to negative evaluation of others. A brief (10 item) version of the FNE was used in the present report and has been shown to have good internal consistency, test–retest reliability, and validity (Collins, Westra, Dozois, & Stewart, 2005; Leary, 1983). The scale showed excellent internal consistency in the present sample (a ¼ :96). Injury Sensitivity Index (ISI). The ISI is a measure of injury/illness sensitivity. The ISI possesses adequate psychometric properties (Taylor, 1993) and has been shown to be distinct from other measures of fundamental fears such as the ASI and FNE (Taylor, 1993). The scale showed good internal consistency in the present sample (a ¼ :91). Covariate. Trait Anxiety (STAI). The STAI is composed of two 20-item scales designed to assess state and trait anxiety (Spielberger, Gorsuch, & Lushese, 1979). Both scales of the STAI have adequate psychometric properties (Knight, Waal-Manning, & Spears, 1983). Only the trait scale, which measures general levels of anxiety, was utilized in the present study. Raw scores on this measure were used for analyses by summing responses to this scale (after reverse scoring negatively worded items).
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Behavioral measure 20% CO2 challenge. A 20% CO2-enriched (balance O2) biological challenge provided a behavioral index of fear responding to a novel stimulus. This type of challenge has been used in other reports and found to be a reliable method of inducing anxiety in the context of unusual bodily sensations (Feldner, Zvolensky, Eifert, & Spira, 2003; Karekla, Forsyth, & Kelly, 2004). To control for different expectancies regarding the consequences of breathing CO2-enriched air, all participants were informed of several possible symptomatic consequences of breathing CO2-enriched air including: breathlessness, dizziness, chest pain, and tachycardia. Participants were not informed regarding the onset, timing, dose, or offset of the inhalation of CO2. Participants underwent a 20-s gas inhalation (20% CO2, 80% O2) administered through a continuous positive air pressure Downs C-Pap Mask with nose clip and head strap. Attached to one free port of a manually controlled 3-Way Stop Cock valve (Hans Rudolph, Inc.) was a 30-L meteorological balloon, which was inflated with the CO2 mixture. Participants breathed the CO2 gas directly from the balloon reservoir to minimize detection from pressurized CO2 to nonpressurized room air. The C-Pap mask was connected to a free 22-mm port of the Stop Cock Valve via 1.8-m of aerosol tubing and the remaining port was left unattached and fed room air. A remote device was used to control of the 3-Way Stop Cock valve for unobtrusive switching between CO2-enriched air and room air. Procedure Participants initially completed the SCID and, if eligible, a battery of self-report measures. Eligible participants were then randomly assigned to one of two conditions (treatment or control). Both conditions involved information delivered via an audio–visual computer presentation lasting approximately 30 min followed by 10 min spent with an experimenter (see Schmidt et al. (2005), for details regarding the intervention). Following the intervention, some of the self-report measures were re-administered and then participants completed a CO2 challenge. At this point, participants were led to a comfortable recliner in a dimly lit sound attenuated chamber and fitted with the CO2 apparatus (e.g., mask). Participants completed an API following a 5-min adaptation period. After approximately 3 min, participants received a 20-s inhalation of CO2-enriched air. Immediately following the inhalation, participants returned to breathing normal room air and completed another API. Community and high school participants received $25 as compensation for the baseline assessment whereas college students received course credit. Results Descriptive data and zero-order relations among theoretically relevant variables Table 1 shows correlations, means and standard deviations of the relevant predictor variables. Note that all measures used in these analyses were completed prior to the biological challenge. The three expectancy factors were moderately intercorrelated (r range: .41–56) suggesting a fair amount of overlap but enough distinctiveness to yield differential predictions. Each of the factors was significantly related to trait anxiety with correlations in the low to mid .30s.
Table 1 Intercorrelations, means and standard deviations among the primary variables of interest
1. 2. 3. 4.
Anxiety Sensitivity (ASI) Fear of Neg Evaluation (FNE) Injury Sensitivity (ISI) Trait Anxiety (STAI)
ASI
FNE
— .51 .56 .36
— .41 .33
ISI
M
SD
— .32
17.0 30.4 23.5 44.6
8.7 12.8 9.4 4.5
Note: N ¼ range from 380 to 404. All p’so.01 STAI M ¼ raw score. ASI ¼ Anxiety Sensitivity Inventory; FNE ¼ Fear of Negative Evaluation (brief version); ISI ¼ Injury Sensitivity Index; STAI ¼ Spielberger Trait Anxiety.
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Table 2 Expectancy factors predicting subjective responding to a 20% CO2 challenge Predicted variable
Predictors in set
DR2
Step 1 Condition STAI Baseline-API-Sxs Step 2a ASI Step 2b FNE Step 2c ISI
0.22
t for each predictor
b
2.12* 2.57* 9.35**
.10 .12 .42
API-symptom total
0.01 2.05*
.11
0.95
.05
0.44
.02
0.00 0.00
API-SUDS Step 1 Condition STAI Baseline-API-SUDS Step 2a ASI Step 2b FNE Step 2c ISI
0.30 2.26* 2.41* 11.63**
.10 .10 .50
0.01 2.51*
.12
2.77**
.13
2.22*
.10
0.01 0.01
Note: API ¼ Acute Panic Inventory; SUDS ¼ Subjective Units of Distress–Anxiety; STAI ¼ Spielberger Trait Anxiety; ASI ¼ Anxiety Sensitivity Inventory; FNE ¼ Fear of Negative Evaluation (brief version); ISI ¼ Injury Sensitivity Index. po:05, po:01.
Expectancy theory components predicting subjective responding to the challenge The primary dependent measures for the challenge component of this study included API symptoms and SUDS. Hierarchical linear regression analyses were performed with each of the primary dependent measures. At level 1 in the model, experimental condition1 and trait anxiety were included as covariates (entered) to ensure any observed effects were not due to these factors. In addition, the baseline variable of the dependent measure was entered to yield a prediction of reactivity. At level 2 in the model, the ASI, FNE, and ISI were entered. Note that these measures were reevaluated following the experimental procedure and this administration was used for the analyses examining the biological challenge. In this model, any observed effects for variables at level 2 in the model are unique and cannot be attributed to variance with factors in level 1 (Cohen & Cohen, 1983). In the first round of analyses, the Expectancy dimensions were entered separately to determine whether any dimension would predict subjective reactivity beyond the effects of trait anxiety. Findings are summarized in Table 2. After controlling for trait anxiety and the relevant baseline variable, we found that the ASI predicted increased symptoms and SUDS. The FNE and ISI did not predict API symptoms but these variables did predict increased SUDS. These analyses suggest that the ASI may be a somewhat better predictor of fearful responding to a CO2 challenge relative to the other Expectancy dimensions. In order to provide a more finegrained analysis of the unique contributions of each Expectancy factor, particularly since they are moderately intercorrelated, regression analyses were repeated with each of the expectancy factors simultaneously entered at level 2. These analyses indicated that the ASI was the only significant predictor of SUDS (b ¼ :15, t ¼ 2:20, 1
Because the treatment condition produced some changes in the cognitive predictors, most notably in the ASI, scores on the measures following the manipulation were utilized. As an additional check that the pattern of findings was not accounted for by the experimental manipulation, all relevant analyses were re-run after excluding participants assigned to the treatment condition. These analyses revealed the same pattern of findings.
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po:05) and API symptoms (b ¼ :18, t ¼ 2:41, po:05) when simultaneously accounting for the FNE and ISI. However, the FNE showed a trend approaching significance (b ¼ :10, t ¼ 1:74, p ¼ :08) in predicting SUDS. Discussion The primary aim of the present report was to ‘‘revisit’’ Expectancy theory, a model developed in the mid1980s that was designed to account for the development of anxiety pathology. Despite some promising findings from each of the three fundamental sensitivities posited by this model, there has been virtually no work on two of the dimensions—fear of negative evaluation and illness/injury sensitivity. Data from the present report suggest specificity for the AS component of Expectancy theory, being related to challengeinduced anxiety. This adds to the discriminant validity of AS in predicting panic symptoms relative to the other sensitivities described by Reiss (1991). Lilienfeld and others have suggested that evaluation of AS must take into account the potential for a higherorder relationship between trait anxiety and the various sensitivities proposed in Expectancy theory (Lilienfeld, Jacob, & Turner, 1989). Although this point has been debated (McNally, 1993), the general logic is that sensitivities should be able to account for unique variance beyond the effects of trait anxiety, which is likely to act as a general vulnerability factor. In the present report, we attempted to address this issue by covarying trait anxiety. This procedure did not tend to change the pattern of findings and suggests that AS is uniquely relevant to anxiety symptoms beyond a general anxiety vulnerability factor. Although the present study provides new insight into the specific nature of Expectancy theory dimensions, there are several limitations that should be acknowledged and also point to additional avenues worthy of investigation. First, the cross-sectional nature of the data prevents definitive conclusions regarding causality. The use of a biological challenge addresses this concerns to some extent. Biological challenge studies have proven useful in the identification of neurobiological as well as psychological predictors of anxiety and panic. The challenge provides a more compelling account that AS may place someone at risk for an anxiety response in the context of novel stimuli. Although the finding that AS is predictive of fearful responding to a CO2 challenge is not novel (Eifert, Zvolensky, Sorrell, Hopko, & Lejuez, 1999; Eke & McNally, 1996; Rapee, Brown, Antony, & Barlow, 1992), the specificity of the finding (compared to FNE and ISI as well as trait anxiety) is novel. Second, the present report assessed anxiety symptoms in a nonclinical sample. Although use of nonclinical samples is very useful in the identification of premorbid risk factors, it would be highly informative if future investigations assessed whether the present findings generalize to clinical samples. Moreover, evaluation of AS and other sensitivities in clinical samples is critical for the evaluation of these factors in the course and maintenance of anxiety pathology. Third, due to the paucity of work on fear of negative evaluation and illness/injury sensitivity, it is unclear the extent to which the FNE and ISI adequately tap into these constructs. For example, the FNE is used as a measure of social anxiety symptoms (Antony, Orsillo, & Roemer, 2001) leading to questions regarding whether it is a discrete measure of a sensitivity versus a measure of the symptoms of social anxiety. Similar criticisms were raised regarding the potential overlap between AS and panic disorder (Lilienfeld et al., 1989). In sum, a challenge remains regarding demonstration of the distinctiveness of fear of negative evaluation and social anxiety disorder. Finally, it should be noted that a number of other factors influence emotional responding to challenge such as daily smoking (Zvolensky & Leen-Feldner, 2005) that were not assessed in the present report. More comprehensive assessments of such variables would be useful to further establish the unique, predictive nature of AS. It is also worth considering that recent reports suggest that AS may be best conceptualized as a discontinuous variable, i.e., a taxon (Bernstein, Zvolensky, Weems et al., 2005; Schmidt, Kotov, Lerew, Joiner, & Ialongo, in press). Furthermore, there are data suggesting that the taxonic form of AS may be particularly useful in predicting anxiety-related outcomes (Bernstein, Zvolensky, Feldner et al., 2005; Zvolensky, Forsyth, Bernstein, & Leen-Feldner, in press). It may be fruitful for future studies to focus on the taxonic nature of AS in the context of predicting fear responding to biological challenge. In the early 1980s, very little was known about AS and its relationship with anxiety pathology. Twenty years later, AS is one of the most promising and best researched psychological risk factors for anxiety problems. The present study provides one more demonstration that anxiety sensitivity is a unique risk for the development of panic-related symptoms.
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Acknowledgements This project was supported by an Ohio Department of Mental Health research grant (737111) and by a National Institute Mental Health grant (MH62056).
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Schmidt, N. B., Eggleston, A. M., Trakowski, J. H., & Smith, J. D. (2005). Does coping predict CO2-induced panic in patients with panic disorder. Behaviour Research and Therapy, 10, 1311–1319. Schmidt, N.B., Eggleston, A.M., Woolaway-Bickel, K., Fitzpatrick, K.K., Vasey, M.W., & Richey, J.A. (2005). Anxiety Sensitivity Amelioration Training (ASAT): A longitudinal primary prevention program targeting cognitive vulnerability. Manuscript under review. Schmidt, N. B., & Joiner, T., Jr. (2002). Structure of the anxiety sensitivity index: Psychometrics and factor structure in a community sample. Journal of Anxiety Disorders, 16, 33–49. Schmidt, N. B., Kotov, R., Lerew, D. R., Joiner, T. E., & Ialongo, N. S. (in press). Evaluating latent discontinuity in cognitive vulnerability to panic: A taxometric investigation. Cognitive Therapy and Research, in press. Schmidt, N. B., Lerew, D. R., & Jackson, R. J. (1997). The role of anxiety sensitivity in the pathogenesis of panic: Prospective evaluation of spontaneous panic attacks during acute stress. Journal of Abnormal Psychology, 106, 355–364. Schmidt, N. B., Lerew, D. R., & Jackson, R. J. (1999). Prospective evaluation of anxiety sensitivity in the pathogenesis of panic: Replication and extension. Journal of Abnormal Psychology, 108, 532–537. Schmidt, N. B., Staab, J. P., Trakowski, J. H., & Sammons, M. (1997). Efficacy of a brief psychosocial treatment for panic disorder in an active duty sample: Implications for military readiness. Military Medicine, 162, 123–129. Schmidt, N. B., Storey, J., Greenberg, B. D., Santiago, H. T., Li, Q., & Murphy, D. L. (2000). Evaluating gene x psychological risk factor effects in the pathogenesis of anxiety: A new model approach. Journal of Abnormal Psychology, 109, 308–320. Schmidt, N. B., Trakowski, J. H., & Staab, J. P. (1997). Extinction of panicogenic effects of a 35% CO2 challenge in patients with panic disorder. Journal of Abnormal Psychology, 106, 630–638. Spielberger, C. D., Gorsuch, R. L., & Lushese, R. E. (1979). Manual for the state—trait anxiety inventory. Palo Alto, CA: Consulting Psychologists Press. Taylor, S. (1993). The structure of fundamental fears. Journal of Behavior Therapy and Experimental Psychiatry, 24, 289–299. Taylor, S. (1999). Anxiety sensitivity: Theory, research and treatment of the fear of anxiety. Mahwah, NJ: Lawrence Erlbaum Associates, Inc. Zinbarg, R. E., Barlow, D. H., & Brown, T. A. (1997). Hierarchical structure and general factor structure saturation of the Anxiety Sensitivity Index: Evidence and implications. Psychological Assessment, 9, 277–284. Zvolensky, M. J., & Eifert, G. H. (2001). A review of psychological factors/processes affecting anxious responding during voluntary hyperventilation and inhalations of carbon dioxide enriched air. Clinical Psychology Review, 21, 375–400. Zvolensky, M. J., Feldner, M. T., Eifert, G. H., & Stewart, S. H. (2001). Evaluating differential predictions of emotional reactivity during repeated 20% carbon dioxide-enriched air challenge. Cognition and Emotion, 15, 767–786. Zvolensky, M. J., Forsyth, J. P., Bernstein, A., & Leen-Feldner, E. W. (in press). A concurrent test of the anxiety sensitivity taxon: Its relation to bodily vigilance and perceptions of control over anxiety-related events in a sample of young adults. Journal of Cognitive Psychotherapy, in press. Zvolensky, M. J., & Leen-Feldner, E. W. (2005). Anxiety and stress vulnerability and substance problems: Theory, empirical evidence, and directions for future research. Clinical Psychology Review, 25, 707–712. Zvolensky, M. J., McNeil, D. W., Porter, C. A., & Stewart, S. H. (2001). Assessment of anxiety sensitivity in young American Indians and Alaska natives. Behaviour Research and Therapy, 39, 477–493.
Further reading Hofmann, S. G., Heinrichs, N., & Moscovitch, D. A. (2004). The nature and expression of social phobia: Toward a new classification. Clinical Psychology Review, 24, 769–797. Stein, D. J., Ono, Y., Tajima, O., & Muller, J. E. (2004). The social anxiety disorder spectrum. Journal of Clinical Psychiatry, 65, 27–33.
Behaviour Research and Therapy 44 (2006) 1681–1688 www.elsevier.com/locate/brat
Shorter communication
Evaluating anxiety sensitivity and other fundamental sensitivities predicting anxiety symptoms and fearful responding to a biological challenge Norman B. Schmidt, Michael Mallott Department of Psychology, Florida State University, Tallahassee, FL 32306, USA Received 13 July 2005; received in revised form 30 November 2005; accepted 6 December 2005
Abstract Fear of arousal symptoms, often referred to as anxiety sensitivity (AS), appears to be associated with risk for anxiety pathology and other Axis I conditions. However, AS is only one of three fundamental components of Reiss’ Expectancy Model proposed to account for the development of anxiety problems. Very little research has focused on the other two components of this model (Fear of Negative Evaluation, Illness/Injury Sensitivity) and the specificity of AS, relative to these other two components, has rarely been evaluated. This study evaluated general and unique associations among all three so-called fundamental sensitivities to fearful responding to a biological challenge in a nonclinical sample (N ¼ 404). Participants were administered a 20-s inhalation of 20% CO2/balance O2. Consistent with hypothesis, only AS uniquely contributed to increased subjective fear responding to the challenge. These findings are consistent with Expectancy Theory in suggesting that the AS component of the model is specific to amplification of fears to arousal cues. r 2005 Elsevier Ltd. All rights reserved. Keywords: Anxiety; Risk factor; Vulnerability; Anxiety disorder
Introduction Converging lines of evidence suggest that anxiety disorders in adulthood may represent manifestations of an underlying constitutional vulnerability or diathesis for anxiety that is partly genetic and variably expressed over the life cycle. An individual’s overall risk for pathology is believed to be a function of personal genetic and nongenetic resiliency and vulnerability factors, environmental risk and protective factors, and interactions among these factors. In terms of nongenetic risks, perhaps one of the best researched psychological risk factors for anxiety is a construct called anxiety sensitivity (AS). AS refers to the extent to which an individual believes that symptoms of anxiety or arousal can have harmful consequences (Reiss & McNally, 1985). A growing body of AS research has focused on establishing this variable as a vulnerability factor in the development of anxiety pathology. Accumulating findings from laboratory (Rapee & Medoro, 1994) and prospective Corresponding author. Tel.: +1 850 644 1707; fax: +1 850 644 7739.
E-mail address: [email protected] (N.B. Schmidt). 0005-7967/$ - see front matter r 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.brat.2005.12.001
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(Schmidt, Lerew, & Jackson, 1997, 1999) studies have provided converging evidence that AS acts as a specific risk factor in the development of anxiety pathology (see Taylor, 1999, for a review). It is notable, however, that AS is only one of three cognitive risk factors posited by Expectancy theory (Reiss & McNally, 1985). Expectancy theory proposed that anxiety problems such as panic attacks and phobias arise from three fundamental sensitivities: (1) AS, (2) fear of negative evaluation, and (3) injury/illness sensitivity. Fear of negative evaluation refers to concerns and fear regarding negative evaluation from others and illness/injury sensitivity is described as fear of injury and illness. Reiss (1991) describes these dimensions as fundamental in the sense that they represent the potential to fear inherently aversive stimuli or events (e.g., humiliation, death). In addition, other common fear reactions or pathologies are believed result from these fundamental sensitivities. For example, fear of aversive bodily perturbations may result in the development of panic attacks or panic disorder. Fear of negative evaluation may result in social anxiety disorder and fear of injury/illness may contribute to the development of generalized anxiety disorder. Despite considerable research on AS, there is very little empirical work on the other two dimensions of Expectancy theory. Some early work suggested that these fundamental dimensions are factorially distinct (Reiss, Peterson, & Gursky, 1988). The distinctiveness of Expectancy factors was later confirmed by Taylor (1993). There are also a handful of studies suggesting that different Expectancy dimensions may be related to phobias and fears (Gursky & Reiss, 1987; McNally & Louro, 1992). For example, in one of the most comprehensive analyses of the relationship among these dimensions and anxiety symptoms, Taylor (1993) found that one or more of the Expectancy dimensions were related to trait anxiety, social fears, phobic avoidance, animal fears and blood injury fears. Despite these initial promising findings, there are virtually no studies of fear of negative evaluation or injury sensitivity since Taylor’s study in the early 1990s. The main aim of the present study is to provide an evaluation of the three dimensions of Expectancy theory in the context of fearful responding to a biological challenge. There is some literature that has evaluated the specificity of AS in terms of biological challenges (see Zvolensky & Eifert, 2001 for a review). For example, AS has been found to be predictive of fearful responding to challenge even after controlling for other relevant diagnostic (Schmidt, Trakowski, & Staab, 1997) psychological (Zvolensky, Feldner, Eifert, & Stewart, 2001) and genetic factors (Schmidt et al., 2000). In the present report, we were interested in testing the discriminant properties of AS, relative to the other dimensions of Expectancy theory, in the context of fearful responding to a biological challenge. Consistent with prior work, we expected that AS would be uniquely associated with challenge-induced panic symptoms and anxiety. Method Participants Participants took part in a longitudinal, primary prevention study (see Schmidt et al., 2005 for additional details). Exclusion criteria for this study include age restrictions (i.e., age range ¼ 14–25) and the presence of any current Axis I diagnosis. Participants were recruited from the Columbus, OH metropolitan area school system (n ¼ 46), the Ohio State University (n ¼ 263), and the Columbus, OH community (n ¼ 96). The sample was relatively young (age M ¼ 19.3, SD ¼ 3.9) with the majority being female (61%). The sample was also primarily white (74%) with 10% African-American, 9% Asian-American, 2% Hispanic, and 3% Other. Completion of college was the most frequently endorsed level of parental education with 30% of mothers and 29% of fathers finishing college. Assessments A multi-modal assessment battery was administered to all participants. This battery consisted of clinicianrated measures as well as self-rated measures. In addition, participants completed a 20% CO2 challenge. Diagnostic interview Psychiatric diagnoses were made using structured diagnostic interviews (SCID-IP; First, Spitzer, Gibbon, & Williams, 1994). Interviews were conducted by advanced graduate students in clinical psychology who had
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received extensive training in SCID administration and scoring. This training included reviewing SCID training tapes, observing taped SCID administration, observing live SCID administration, and conducting SCID interviews with a trained interviewer. Interviewers received feedback throughout this process until they demonstrated high reliability. These same training procedures have been used in other projects in our laboratory that have generated high inter-rater reliability for all Axis I diagnoses (Schmidt, Staab, Trakowski, & Sammons, 1997). A consensus method of diagnosis was used at weekly staff meetings where positive diagnostic findings were reviewed. The typical inter-rater reliability evaluation was not conducted due to participant selection criteria at baseline (i.e., absence of Axis I pathology). Self-report measures Dependent variables. Acute Panic Inventory (API). The API is a 17-item inventory for assessing symptoms of arousal associated with panic attacks (Liebowitz, Gorman, Fyer, Dillon, & Klein, 1984). The API has been used extensively in panic provocation studies (Fyer, Uy, Martinez, & Goetz, 1987; Gorman et al., 1994; Harrison et al., 1989; Schmidt, Eggleston, Trakowski, & Smith, in press). Participants rate the severity of each symptom from 0 (absent) to 3 (severe). The API includes a SUDS rating of self-reported anxiety (0—no anxiety, 100—extreme anxiety). Predictor variables—expectancy dimensions. The three expectancy dimensions were operationalized using three self-report measures. As is commonly done, the Anxiety Sensitivity Inventory (ASI) (Reiss, Peterson, Gursky, & McNally, 1986) was used to measure AS. Similar to the Taylor (1993) report, the brief Fear of Negative Evaluation scale (Leary, 1983) was used to measure Fear of Negative Evaluation and the Injury Sensitivity Index (Taylor, 1993) was used to measure Illness/Injury Sensitivity. Unlike the Taylor study, which conducted a factor analysis of items from each of these scales and used the resulting factors for analyses, we simply used the scales for a number of reasons including: (1) for ease of interpretability, (2) Taylor’s factor analysis found that the scales largely cohered with the exception of some of the social items from the ASI loading on the Fear of Negative Evaluation factor, and (3) in the present study, factor analytically derived subscales yielded a pattern of findings comparable to those reported with the original scales. ASI. The ASI (Reiss et al., 1986) is a 16 item self-report measure of the fear of bodily sensations associated with arousal. Each item consists of a possible negative consequence of anxiety symptoms. The structure of the ASI is hierarchical and consists of three first-order factors (i.e., AS-physical concerns, AS-mental incapacitation concerns, and AS-social concerns) (Zinbarg, Barlow, & Brown, 1997). The factor structure and psychometric properties of the ASI have been replicated across diverse populations, testifying to its broad-based applicability (Carter, Miller, Sbrocco, Suchday, & Lewis, 1999; Schmidt & Joiner, 2002; Zvolensky, McNeil, Porter, & Stewart, 2001). The scale showed good internal consistency in the present sample (a ¼ :87). Fear of negative evaluation (FNE). The FNE is a popular measure of expectation and distress related to negative evaluation of others. A brief (10 item) version of the FNE was used in the present report and has been shown to have good internal consistency, test–retest reliability, and validity (Collins, Westra, Dozois, & Stewart, 2005; Leary, 1983). The scale showed excellent internal consistency in the present sample (a ¼ :96). Injury Sensitivity Index (ISI). The ISI is a measure of injury/illness sensitivity. The ISI possesses adequate psychometric properties (Taylor, 1993) and has been shown to be distinct from other measures of fundamental fears such as the ASI and FNE (Taylor, 1993). The scale showed good internal consistency in the present sample (a ¼ :91). Covariate. Trait Anxiety (STAI). The STAI is composed of two 20-item scales designed to assess state and trait anxiety (Spielberger, Gorsuch, & Lushese, 1979). Both scales of the STAI have adequate psychometric properties (Knight, Waal-Manning, & Spears, 1983). Only the trait scale, which measures general levels of anxiety, was utilized in the present study. Raw scores on this measure were used for analyses by summing responses to this scale (after reverse scoring negatively worded items).
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Behavioral measure 20% CO2 challenge. A 20% CO2-enriched (balance O2) biological challenge provided a behavioral index of fear responding to a novel stimulus. This type of challenge has been used in other reports and found to be a reliable method of inducing anxiety in the context of unusual bodily sensations (Feldner, Zvolensky, Eifert, & Spira, 2003; Karekla, Forsyth, & Kelly, 2004). To control for different expectancies regarding the consequences of breathing CO2-enriched air, all participants were informed of several possible symptomatic consequences of breathing CO2-enriched air including: breathlessness, dizziness, chest pain, and tachycardia. Participants were not informed regarding the onset, timing, dose, or offset of the inhalation of CO2. Participants underwent a 20-s gas inhalation (20% CO2, 80% O2) administered through a continuous positive air pressure Downs C-Pap Mask with nose clip and head strap. Attached to one free port of a manually controlled 3-Way Stop Cock valve (Hans Rudolph, Inc.) was a 30-L meteorological balloon, which was inflated with the CO2 mixture. Participants breathed the CO2 gas directly from the balloon reservoir to minimize detection from pressurized CO2 to nonpressurized room air. The C-Pap mask was connected to a free 22-mm port of the Stop Cock Valve via 1.8-m of aerosol tubing and the remaining port was left unattached and fed room air. A remote device was used to control of the 3-Way Stop Cock valve for unobtrusive switching between CO2-enriched air and room air. Procedure Participants initially completed the SCID and, if eligible, a battery of self-report measures. Eligible participants were then randomly assigned to one of two conditions (treatment or control). Both conditions involved information delivered via an audio–visual computer presentation lasting approximately 30 min followed by 10 min spent with an experimenter (see Schmidt et al. (2005), for details regarding the intervention). Following the intervention, some of the self-report measures were re-administered and then participants completed a CO2 challenge. At this point, participants were led to a comfortable recliner in a dimly lit sound attenuated chamber and fitted with the CO2 apparatus (e.g., mask). Participants completed an API following a 5-min adaptation period. After approximately 3 min, participants received a 20-s inhalation of CO2-enriched air. Immediately following the inhalation, participants returned to breathing normal room air and completed another API. Community and high school participants received $25 as compensation for the baseline assessment whereas college students received course credit. Results Descriptive data and zero-order relations among theoretically relevant variables Table 1 shows correlations, means and standard deviations of the relevant predictor variables. Note that all measures used in these analyses were completed prior to the biological challenge. The three expectancy factors were moderately intercorrelated (r range: .41–56) suggesting a fair amount of overlap but enough distinctiveness to yield differential predictions. Each of the factors was significantly related to trait anxiety with correlations in the low to mid .30s.
Table 1 Intercorrelations, means and standard deviations among the primary variables of interest
1. 2. 3. 4.
Anxiety Sensitivity (ASI) Fear of Neg Evaluation (FNE) Injury Sensitivity (ISI) Trait Anxiety (STAI)
ASI
FNE
— .51 .56 .36
— .41 .33
ISI
M
SD
— .32
17.0 30.4 23.5 44.6
8.7 12.8 9.4 4.5
Note: N ¼ range from 380 to 404. All p’so.01 STAI M ¼ raw score. ASI ¼ Anxiety Sensitivity Inventory; FNE ¼ Fear of Negative Evaluation (brief version); ISI ¼ Injury Sensitivity Index; STAI ¼ Spielberger Trait Anxiety.
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Table 2 Expectancy factors predicting subjective responding to a 20% CO2 challenge Predicted variable
Predictors in set
DR2
Step 1 Condition STAI Baseline-API-Sxs Step 2a ASI Step 2b FNE Step 2c ISI
0.22
t for each predictor
b
2.12* 2.57* 9.35**
.10 .12 .42
API-symptom total
0.01 2.05*
.11
0.95
.05
0.44
.02
0.00 0.00
API-SUDS Step 1 Condition STAI Baseline-API-SUDS Step 2a ASI Step 2b FNE Step 2c ISI
0.30 2.26* 2.41* 11.63**
.10 .10 .50
0.01 2.51*
.12
2.77**
.13
2.22*
.10
0.01 0.01
Note: API ¼ Acute Panic Inventory; SUDS ¼ Subjective Units of Distress–Anxiety; STAI ¼ Spielberger Trait Anxiety; ASI ¼ Anxiety Sensitivity Inventory; FNE ¼ Fear of Negative Evaluation (brief version); ISI ¼ Injury Sensitivity Index. po:05, po:01.
Expectancy theory components predicting subjective responding to the challenge The primary dependent measures for the challenge component of this study included API symptoms and SUDS. Hierarchical linear regression analyses were performed with each of the primary dependent measures. At level 1 in the model, experimental condition1 and trait anxiety were included as covariates (entered) to ensure any observed effects were not due to these factors. In addition, the baseline variable of the dependent measure was entered to yield a prediction of reactivity. At level 2 in the model, the ASI, FNE, and ISI were entered. Note that these measures were reevaluated following the experimental procedure and this administration was used for the analyses examining the biological challenge. In this model, any observed effects for variables at level 2 in the model are unique and cannot be attributed to variance with factors in level 1 (Cohen & Cohen, 1983). In the first round of analyses, the Expectancy dimensions were entered separately to determine whether any dimension would predict subjective reactivity beyond the effects of trait anxiety. Findings are summarized in Table 2. After controlling for trait anxiety and the relevant baseline variable, we found that the ASI predicted increased symptoms and SUDS. The FNE and ISI did not predict API symptoms but these variables did predict increased SUDS. These analyses suggest that the ASI may be a somewhat better predictor of fearful responding to a CO2 challenge relative to the other Expectancy dimensions. In order to provide a more finegrained analysis of the unique contributions of each Expectancy factor, particularly since they are moderately intercorrelated, regression analyses were repeated with each of the expectancy factors simultaneously entered at level 2. These analyses indicated that the ASI was the only significant predictor of SUDS (b ¼ :15, t ¼ 2:20, 1
Because the treatment condition produced some changes in the cognitive predictors, most notably in the ASI, scores on the measures following the manipulation were utilized. As an additional check that the pattern of findings was not accounted for by the experimental manipulation, all relevant analyses were re-run after excluding participants assigned to the treatment condition. These analyses revealed the same pattern of findings.
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po:05) and API symptoms (b ¼ :18, t ¼ 2:41, po:05) when simultaneously accounting for the FNE and ISI. However, the FNE showed a trend approaching significance (b ¼ :10, t ¼ 1:74, p ¼ :08) in predicting SUDS. Discussion The primary aim of the present report was to ‘‘revisit’’ Expectancy theory, a model developed in the mid1980s that was designed to account for the development of anxiety pathology. Despite some promising findings from each of the three fundamental sensitivities posited by this model, there has been virtually no work on two of the dimensions—fear of negative evaluation and illness/injury sensitivity. Data from the present report suggest specificity for the AS component of Expectancy theory, being related to challengeinduced anxiety. This adds to the discriminant validity of AS in predicting panic symptoms relative to the other sensitivities described by Reiss (1991). Lilienfeld and others have suggested that evaluation of AS must take into account the potential for a higherorder relationship between trait anxiety and the various sensitivities proposed in Expectancy theory (Lilienfeld, Jacob, & Turner, 1989). Although this point has been debated (McNally, 1993), the general logic is that sensitivities should be able to account for unique variance beyond the effects of trait anxiety, which is likely to act as a general vulnerability factor. In the present report, we attempted to address this issue by covarying trait anxiety. This procedure did not tend to change the pattern of findings and suggests that AS is uniquely relevant to anxiety symptoms beyond a general anxiety vulnerability factor. Although the present study provides new insight into the specific nature of Expectancy theory dimensions, there are several limitations that should be acknowledged and also point to additional avenues worthy of investigation. First, the cross-sectional nature of the data prevents definitive conclusions regarding causality. The use of a biological challenge addresses this concerns to some extent. Biological challenge studies have proven useful in the identification of neurobiological as well as psychological predictors of anxiety and panic. The challenge provides a more compelling account that AS may place someone at risk for an anxiety response in the context of novel stimuli. Although the finding that AS is predictive of fearful responding to a CO2 challenge is not novel (Eifert, Zvolensky, Sorrell, Hopko, & Lejuez, 1999; Eke & McNally, 1996; Rapee, Brown, Antony, & Barlow, 1992), the specificity of the finding (compared to FNE and ISI as well as trait anxiety) is novel. Second, the present report assessed anxiety symptoms in a nonclinical sample. Although use of nonclinical samples is very useful in the identification of premorbid risk factors, it would be highly informative if future investigations assessed whether the present findings generalize to clinical samples. Moreover, evaluation of AS and other sensitivities in clinical samples is critical for the evaluation of these factors in the course and maintenance of anxiety pathology. Third, due to the paucity of work on fear of negative evaluation and illness/injury sensitivity, it is unclear the extent to which the FNE and ISI adequately tap into these constructs. For example, the FNE is used as a measure of social anxiety symptoms (Antony, Orsillo, & Roemer, 2001) leading to questions regarding whether it is a discrete measure of a sensitivity versus a measure of the symptoms of social anxiety. Similar criticisms were raised regarding the potential overlap between AS and panic disorder (Lilienfeld et al., 1989). In sum, a challenge remains regarding demonstration of the distinctiveness of fear of negative evaluation and social anxiety disorder. Finally, it should be noted that a number of other factors influence emotional responding to challenge such as daily smoking (Zvolensky & Leen-Feldner, 2005) that were not assessed in the present report. More comprehensive assessments of such variables would be useful to further establish the unique, predictive nature of AS. It is also worth considering that recent reports suggest that AS may be best conceptualized as a discontinuous variable, i.e., a taxon (Bernstein, Zvolensky, Weems et al., 2005; Schmidt, Kotov, Lerew, Joiner, & Ialongo, in press). Furthermore, there are data suggesting that the taxonic form of AS may be particularly useful in predicting anxiety-related outcomes (Bernstein, Zvolensky, Feldner et al., 2005; Zvolensky, Forsyth, Bernstein, & Leen-Feldner, in press). It may be fruitful for future studies to focus on the taxonic nature of AS in the context of predicting fear responding to biological challenge. In the early 1980s, very little was known about AS and its relationship with anxiety pathology. Twenty years later, AS is one of the most promising and best researched psychological risk factors for anxiety problems. The present study provides one more demonstration that anxiety sensitivity is a unique risk for the development of panic-related symptoms.
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Acknowledgements This project was supported by an Ohio Department of Mental Health research grant (737111) and by a National Institute Mental Health grant (MH62056).
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Schmidt, N. B., Eggleston, A. M., Trakowski, J. H., & Smith, J. D. (2005). Does coping predict CO2-induced panic in patients with panic disorder. Behaviour Research and Therapy, 10, 1311–1319. Schmidt, N.B., Eggleston, A.M., Woolaway-Bickel, K., Fitzpatrick, K.K., Vasey, M.W., & Richey, J.A. (2005). Anxiety Sensitivity Amelioration Training (ASAT): A longitudinal primary prevention program targeting cognitive vulnerability. Manuscript under review. Schmidt, N. B., & Joiner, T., Jr. (2002). Structure of the anxiety sensitivity index: Psychometrics and factor structure in a community sample. Journal of Anxiety Disorders, 16, 33–49. Schmidt, N. B., Kotov, R., Lerew, D. R., Joiner, T. E., & Ialongo, N. S. (in press). Evaluating latent discontinuity in cognitive vulnerability to panic: A taxometric investigation. Cognitive Therapy and Research, in press. Schmidt, N. B., Lerew, D. R., & Jackson, R. J. (1997). The role of anxiety sensitivity in the pathogenesis of panic: Prospective evaluation of spontaneous panic attacks during acute stress. Journal of Abnormal Psychology, 106, 355–364. Schmidt, N. B., Lerew, D. R., & Jackson, R. J. (1999). Prospective evaluation of anxiety sensitivity in the pathogenesis of panic: Replication and extension. Journal of Abnormal Psychology, 108, 532–537. Schmidt, N. B., Staab, J. P., Trakowski, J. H., & Sammons, M. (1997). Efficacy of a brief psychosocial treatment for panic disorder in an active duty sample: Implications for military readiness. Military Medicine, 162, 123–129. Schmidt, N. B., Storey, J., Greenberg, B. D., Santiago, H. T., Li, Q., & Murphy, D. L. (2000). Evaluating gene x psychological risk factor effects in the pathogenesis of anxiety: A new model approach. Journal of Abnormal Psychology, 109, 308–320. Schmidt, N. B., Trakowski, J. H., & Staab, J. P. (1997). Extinction of panicogenic effects of a 35% CO2 challenge in patients with panic disorder. Journal of Abnormal Psychology, 106, 630–638. Spielberger, C. D., Gorsuch, R. L., & Lushese, R. E. (1979). Manual for the state—trait anxiety inventory. Palo Alto, CA: Consulting Psychologists Press. Taylor, S. (1993). The structure of fundamental fears. Journal of Behavior Therapy and Experimental Psychiatry, 24, 289–299. Taylor, S. (1999). Anxiety sensitivity: Theory, research and treatment of the fear of anxiety. Mahwah, NJ: Lawrence Erlbaum Associates, Inc. Zinbarg, R. E., Barlow, D. H., & Brown, T. A. (1997). Hierarchical structure and general factor structure saturation of the Anxiety Sensitivity Index: Evidence and implications. Psychological Assessment, 9, 277–284. Zvolensky, M. J., & Eifert, G. H. (2001). A review of psychological factors/processes affecting anxious responding during voluntary hyperventilation and inhalations of carbon dioxide enriched air. Clinical Psychology Review, 21, 375–400. Zvolensky, M. J., Feldner, M. T., Eifert, G. H., & Stewart, S. H. (2001). Evaluating differential predictions of emotional reactivity during repeated 20% carbon dioxide-enriched air challenge. Cognition and Emotion, 15, 767–786. Zvolensky, M. J., Forsyth, J. P., Bernstein, A., & Leen-Feldner, E. W. (in press). A concurrent test of the anxiety sensitivity taxon: Its relation to bodily vigilance and perceptions of control over anxiety-related events in a sample of young adults. Journal of Cognitive Psychotherapy, in press. Zvolensky, M. J., & Leen-Feldner, E. W. (2005). Anxiety and stress vulnerability and substance problems: Theory, empirical evidence, and directions for future research. Clinical Psychology Review, 25, 707–712. Zvolensky, M. J., McNeil, D. W., Porter, C. A., & Stewart, S. H. (2001). Assessment of anxiety sensitivity in young American Indians and Alaska natives. Behaviour Research and Therapy, 39, 477–493.
Further reading Hofmann, S. G., Heinrichs, N., & Moscovitch, D. A. (2004). The nature and expression of social phobia: Toward a new classification. Clinical Psychology Review, 24, 769–797. Stein, D. J., Ono, Y., Tajima, O., & Muller, J. E. (2004). The social anxiety disorder spectrum. Journal of Clinical Psychiatry, 65, 27–33.