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Generalized anxiety and panic disorders: Response to Cox, Cohen, Direnfeld, and Swinson (1996)
Pergamon
Behav. Res. Ther. Vol. 34, No. 11/12, pp. 955-957, 1996 Copyright © 1996 Elsevier Science Ltd Printed in Great Britain. All rights reserved S0005-7967(96)00059-9 0005-7967/96 $15.00 + 0.00
GENERALIZED ANXIETY AND PANIC DISORDERS: RESPONSE TO COX, COHEN, DIRENFELD, AND SWINSON
(1996)
ROBERT A. STEER ~'* and AARON T. BECK 2 ~Department of Psychiatry, University of Medicine and Dentistry of New Jersey, School of Osteopathic Medicine, Stratford, NJ 08084-1350, U.S.A. and 2Beck Institute for Cognitive Therapy and Research, Bala Cynwyd, PA, U.S.A. (Received 23 May 1996) Summary--Contrary to the contention of Cox, Cohen, Direnfeld and Swinson (1996, Behaviour Research and Therapy, 34, 949-954) that the Beck Anxiety Inventory (BAI; Beck & Steer, 1993, Manual for the Beck Anxiety Inventory) measures primarily symptoms associated with panic attacks rather than anxiety in general, we propose that the higher level of anxiety found in patients with panic disorders not only is not an artifact of the BAI's symptom content, but patients with panic disorders truly have more anxiety than patients with other types of anxiety disorders. Furthermore, the BAI contains symptoms present in other anxiety disorders, besides panic disorder, and specifically includes 11 symptoms of generalized anxiety disorder (GAD). The BAI and revised Hamilton Anxiety Rating Scale (HARS-R; Riskind, Beck, Brown & Steer, 1987, Journal of Nervous and Mental Disease, 175, 474479) scores of 274 (69%) outpatients with panic disorders and 123 (31%) outpatients with GAD were found to differentiate these two diagnostic groups equally and significantly. The panic disorder outpatients had higher scores on both the BAI and the HARS-R than did the GAD patients. Thus, Cox et al.'s (1996) speculation about the BAI's yielding spuriously high levels of anxiety in patients with panic disorders revives an important issue relevant to the relation of panic disorder to GAD. Copyright © 1996 Elsevier Science Ltd
To the question "Does the Beck Anxiety Inventory measure anything beyond panic attack symptoms?", Cox, Cohen, Direnfeld and Swinson (1996) answer that the "BAI appears to be confounded with, or actually measures, panic attacks rather than anxiety in general" (p. 949). We respond strongly, "Yes!" to the question for the following reason: 10 of the 11 symptoms in the Beck Anxiety Inventory (BAI; Beck & Steer, 1993) that Cox et al. (1996) might consider to be "panic-centric" are listed in the Diagnostic and Statistical Manual of Mental Disorders (3rd ed., rev.) (DSM-III-R; American Psychiatric Association, 1987) as criteria for diagnosing generalized anxiety disorder (GAD). Moreover, 11 out of the 18 symptoms listed for GAD as well as 11 out of the 13 symptoms in the DSM-III-R for diagnosing panic disorders are contained in the BAI. Cox et al. (1996) do not mention that 11 BAI symptoms are reflective of GAD, nor do they discuss that "panic-centric" symptoms are present in other anxiety disorders. For example, mild to moderate symptoms of heart pounding, sweating, and difficulty in breathing, are often described by patients diagnosed with GAD and simple and social phobias. Such symptoms are representative of anxiety in general and are not unique to panic attacks. (Clark & Watson, 1991). Other features than simply symptoms differentiate patients with panic disorder from those with other types of anxiety disorders. For example in the Diagnostic and Statistical Manual of Mental Disorders (4th ed.) (DSM-IV; American Psychiatric Association, 1994), a panic attack must specifically reflect symptoms that develop suddenly and rapidly accelerate to peak levels of distress within 10 minutes. Cox et al. (1996) support their contention about the BAI's being too "panic-centric" by citing studies by Beck and Steer (1993) and Fydrich, Dowdall and Chambless (1992) in which patients with panic disorders were found to describe significantly higher levels of anxiety on the BAI than did patients with other types of anxiety disorders. In contrast, Cox et al. (1996) cite a *Author for correspondence. 955
956
Robert A. Steer and Aaron T. Beck
study by Taylor, Koch and McNally (1992) in which patients with panic disorders did not describe more anxiety than did patients with other types of anxiety when a different measure of self-reported anxiety, the Y-Form of the State Trait Anxiety Scale (Spielberger, 1983), was used. According to Cox et al. (1996), the higher level of anxiety measured by the BAI in patients with panic disorders might simply be attributable to the panic patients' endorsing the "panic-centric" symptoms. The validity of such a diagnostic difference can be tested by using another method of measurement, such as a standard, clinical rating scale, rather than a self-report instrument, and by comparing the effectiveness of the differentiation obtained by the clinical rating scale with that afforded by the BAI. For example, the Hamilton Anxiety Rating Scale (HARS; Hamilton, 1959) was constructed, 25 years before the description of panic disorders in the DSM-III-R, to assess the overall severity of anxiety in "patients already suffering from neurotic anxiety states" (p. 50); panic-attack related symptoms were not specifically added to its content. Therefore, to test the hypothesis that clinical ratings of anxiety and the BAI would be equally effective in differentiating between patients with panic disorders and patients with other types of anxiety disorders, we drew a sample of 397 outpatients from the computerized database of the University of Pennsylvania Center for Cognitive Therapy who had been diagnosed with principal DSM-III-R panic or GAD disorders according to the Structured Clinical Interview for DSM-III-R (SCID; Spitzer, Williams, Gibbon & First, 1990). The revised Hamilton Anxiety Rating Scale (HARS-R; Riskind, Beck, Brown & Steer, 1987) and BAI total scores were then compared with respect to distinguishing between outpatients with panic disorders and those with GAD. There were 242 (61%) women and 155 (39%) men, with a mean age of 34.46 (SD = 10.33) yr. The ethnic composition was 380 (96%) White, 11 Black (3%) and 6 (1%) other. There were 114 (29%) outpatients with panic disorder without agrophobia, 160 (40%) with panic disorder with agrophobia, and 123 (31%) with GAD. The mean BAI and HARS-R scores of the 274 outpatients with panic disorders were, respectively, 27.11 (SD = 13.73) and 18.69 (SD = 8.11), and the mean BAI and HARS-R scores of the 123 outpatients with GAD were, respectively, 20.02 (SD = 9.95) and 15.91 (SD = 6.72). The outpatients with panic disorders described significantly higher levels of self-reported anxiety and were clinically rated as more anxious than the outpatients with GAD, Wilks' lambda = 0.94, MANOVA F(2,394)= 13.47, P < 0.001. Most importantly, the point-biserial correlations (effect sizes) of the BAI and the HARS-R with diagnostic group (GAD = 0, Panic Disorder = 1) representing the magnitudes of the differentiation between the two groups afforded by both scales were statistically comparable at 0.25 and 0.17, respectively, Hotelling t(376) = 1.69, NS. The correlation between the BAI and the HARS-R was 0.55, P < 0.001. This latter correlation was, in turn, typical of that found between self-reported and clinical rating scales of anxiety according to Clark and Watson's (1991) review of the literature. CONCLUSION Based on the present analyses, the high anxiety score on the BAI in patients diagnosed with panic disorders is not spurious. The article by Cox et al. (1996), however, underscores a very important consideration that has been largely overlooked by researchers of panic disorder: patients with panic disorders have a high level of persistent clinical anxiety in addition to their panic attack symptomatology. Does this suggest that panic disorder may, in some cases at least, be intrinsically related to GAD? REFERENCES American Psychiatric Association (1987). Diagnostic and statistical manual of mental disorders (3rd ed., rev.). Washington,DC: Author. American PsychiatricAssociation (1994). Diagnostic and statistical manual of mental disorders (4th ed.). Washington, DC: Author. Beck, A. T., & Steer, R. A. (1993). Manual for the Beck Anxiety Inventory. San Antonio, TX: Psychological Corporation.
Response to Cox
957
Clark, L. A., & Watson, D. (1991). Tripartite model of anxiety and depression: psychometric evidence and taxonomic implications. Journal of Abnormal Psychology, 100, 316-336. Cox, B. J., Cohen, E., Direnfeld, D. M., & Swinson, R. P. (1996). Does the Beck Anxiety Inventory measure anything beyond panic attack symptoms? Behaviour Research and Therapy, 34, 949-954. Fydrich, T., Dowdall, D., & Chambless, D. L. (1992). Reliability and validity of the Beck Anxiety Inventory. Journal of Anxiety Disorders, 6, 55-61. Hamilton, M. (1959). The assessment of anxiety states by rating. British Journal of Medical Psychology, 32, 50-55. Riskind, J. H., Beck, A. T., Brown, G., & Steer, R. A. (1987). Taking the measure of anxiety and depression: validity of the reconstructed Hamilton scales. Journal of Nervous and Mental Disease, 175, 474-479. Spielberger, C. D. (1983). Manual for the State-Trait Anxiety Inventory (Form Y). Palo Alto, CA: Consulting Psychologists Press. Spitzer, R. L., Williams, J. B. W., Gibbon, M., & First, M. B. (1990). User's guide for the Structured Clinical Interview for DSM-III-R. Washington, DC: American Psychiatric Press. Taylor, S., Koch, W. J., & McNally, R. J. (1992). How does anxiety sensitivity vary across the anxiety disorders? Journal of Anxiety Disorders, 6, 249-259.
BRT34/lI-12--E
Behav. Res. Ther. Vol. 34, No. 11/12, pp. 955-957, 1996 Copyright © 1996 Elsevier Science Ltd Printed in Great Britain. All rights reserved S0005-7967(96)00059-9 0005-7967/96 $15.00 + 0.00
GENERALIZED ANXIETY AND PANIC DISORDERS: RESPONSE TO COX, COHEN, DIRENFELD, AND SWINSON
(1996)
ROBERT A. STEER ~'* and AARON T. BECK 2 ~Department of Psychiatry, University of Medicine and Dentistry of New Jersey, School of Osteopathic Medicine, Stratford, NJ 08084-1350, U.S.A. and 2Beck Institute for Cognitive Therapy and Research, Bala Cynwyd, PA, U.S.A. (Received 23 May 1996) Summary--Contrary to the contention of Cox, Cohen, Direnfeld and Swinson (1996, Behaviour Research and Therapy, 34, 949-954) that the Beck Anxiety Inventory (BAI; Beck & Steer, 1993, Manual for the Beck Anxiety Inventory) measures primarily symptoms associated with panic attacks rather than anxiety in general, we propose that the higher level of anxiety found in patients with panic disorders not only is not an artifact of the BAI's symptom content, but patients with panic disorders truly have more anxiety than patients with other types of anxiety disorders. Furthermore, the BAI contains symptoms present in other anxiety disorders, besides panic disorder, and specifically includes 11 symptoms of generalized anxiety disorder (GAD). The BAI and revised Hamilton Anxiety Rating Scale (HARS-R; Riskind, Beck, Brown & Steer, 1987, Journal of Nervous and Mental Disease, 175, 474479) scores of 274 (69%) outpatients with panic disorders and 123 (31%) outpatients with GAD were found to differentiate these two diagnostic groups equally and significantly. The panic disorder outpatients had higher scores on both the BAI and the HARS-R than did the GAD patients. Thus, Cox et al.'s (1996) speculation about the BAI's yielding spuriously high levels of anxiety in patients with panic disorders revives an important issue relevant to the relation of panic disorder to GAD. Copyright © 1996 Elsevier Science Ltd
To the question "Does the Beck Anxiety Inventory measure anything beyond panic attack symptoms?", Cox, Cohen, Direnfeld and Swinson (1996) answer that the "BAI appears to be confounded with, or actually measures, panic attacks rather than anxiety in general" (p. 949). We respond strongly, "Yes!" to the question for the following reason: 10 of the 11 symptoms in the Beck Anxiety Inventory (BAI; Beck & Steer, 1993) that Cox et al. (1996) might consider to be "panic-centric" are listed in the Diagnostic and Statistical Manual of Mental Disorders (3rd ed., rev.) (DSM-III-R; American Psychiatric Association, 1987) as criteria for diagnosing generalized anxiety disorder (GAD). Moreover, 11 out of the 18 symptoms listed for GAD as well as 11 out of the 13 symptoms in the DSM-III-R for diagnosing panic disorders are contained in the BAI. Cox et al. (1996) do not mention that 11 BAI symptoms are reflective of GAD, nor do they discuss that "panic-centric" symptoms are present in other anxiety disorders. For example, mild to moderate symptoms of heart pounding, sweating, and difficulty in breathing, are often described by patients diagnosed with GAD and simple and social phobias. Such symptoms are representative of anxiety in general and are not unique to panic attacks. (Clark & Watson, 1991). Other features than simply symptoms differentiate patients with panic disorder from those with other types of anxiety disorders. For example in the Diagnostic and Statistical Manual of Mental Disorders (4th ed.) (DSM-IV; American Psychiatric Association, 1994), a panic attack must specifically reflect symptoms that develop suddenly and rapidly accelerate to peak levels of distress within 10 minutes. Cox et al. (1996) support their contention about the BAI's being too "panic-centric" by citing studies by Beck and Steer (1993) and Fydrich, Dowdall and Chambless (1992) in which patients with panic disorders were found to describe significantly higher levels of anxiety on the BAI than did patients with other types of anxiety disorders. In contrast, Cox et al. (1996) cite a *Author for correspondence. 955
956
Robert A. Steer and Aaron T. Beck
study by Taylor, Koch and McNally (1992) in which patients with panic disorders did not describe more anxiety than did patients with other types of anxiety when a different measure of self-reported anxiety, the Y-Form of the State Trait Anxiety Scale (Spielberger, 1983), was used. According to Cox et al. (1996), the higher level of anxiety measured by the BAI in patients with panic disorders might simply be attributable to the panic patients' endorsing the "panic-centric" symptoms. The validity of such a diagnostic difference can be tested by using another method of measurement, such as a standard, clinical rating scale, rather than a self-report instrument, and by comparing the effectiveness of the differentiation obtained by the clinical rating scale with that afforded by the BAI. For example, the Hamilton Anxiety Rating Scale (HARS; Hamilton, 1959) was constructed, 25 years before the description of panic disorders in the DSM-III-R, to assess the overall severity of anxiety in "patients already suffering from neurotic anxiety states" (p. 50); panic-attack related symptoms were not specifically added to its content. Therefore, to test the hypothesis that clinical ratings of anxiety and the BAI would be equally effective in differentiating between patients with panic disorders and patients with other types of anxiety disorders, we drew a sample of 397 outpatients from the computerized database of the University of Pennsylvania Center for Cognitive Therapy who had been diagnosed with principal DSM-III-R panic or GAD disorders according to the Structured Clinical Interview for DSM-III-R (SCID; Spitzer, Williams, Gibbon & First, 1990). The revised Hamilton Anxiety Rating Scale (HARS-R; Riskind, Beck, Brown & Steer, 1987) and BAI total scores were then compared with respect to distinguishing between outpatients with panic disorders and those with GAD. There were 242 (61%) women and 155 (39%) men, with a mean age of 34.46 (SD = 10.33) yr. The ethnic composition was 380 (96%) White, 11 Black (3%) and 6 (1%) other. There were 114 (29%) outpatients with panic disorder without agrophobia, 160 (40%) with panic disorder with agrophobia, and 123 (31%) with GAD. The mean BAI and HARS-R scores of the 274 outpatients with panic disorders were, respectively, 27.11 (SD = 13.73) and 18.69 (SD = 8.11), and the mean BAI and HARS-R scores of the 123 outpatients with GAD were, respectively, 20.02 (SD = 9.95) and 15.91 (SD = 6.72). The outpatients with panic disorders described significantly higher levels of self-reported anxiety and were clinically rated as more anxious than the outpatients with GAD, Wilks' lambda = 0.94, MANOVA F(2,394)= 13.47, P < 0.001. Most importantly, the point-biserial correlations (effect sizes) of the BAI and the HARS-R with diagnostic group (GAD = 0, Panic Disorder = 1) representing the magnitudes of the differentiation between the two groups afforded by both scales were statistically comparable at 0.25 and 0.17, respectively, Hotelling t(376) = 1.69, NS. The correlation between the BAI and the HARS-R was 0.55, P < 0.001. This latter correlation was, in turn, typical of that found between self-reported and clinical rating scales of anxiety according to Clark and Watson's (1991) review of the literature. CONCLUSION Based on the present analyses, the high anxiety score on the BAI in patients diagnosed with panic disorders is not spurious. The article by Cox et al. (1996), however, underscores a very important consideration that has been largely overlooked by researchers of panic disorder: patients with panic disorders have a high level of persistent clinical anxiety in addition to their panic attack symptomatology. Does this suggest that panic disorder may, in some cases at least, be intrinsically related to GAD? REFERENCES American Psychiatric Association (1987). Diagnostic and statistical manual of mental disorders (3rd ed., rev.). Washington,DC: Author. American PsychiatricAssociation (1994). Diagnostic and statistical manual of mental disorders (4th ed.). Washington, DC: Author. Beck, A. T., & Steer, R. A. (1993). Manual for the Beck Anxiety Inventory. San Antonio, TX: Psychological Corporation.
Response to Cox
957
Clark, L. A., & Watson, D. (1991). Tripartite model of anxiety and depression: psychometric evidence and taxonomic implications. Journal of Abnormal Psychology, 100, 316-336. Cox, B. J., Cohen, E., Direnfeld, D. M., & Swinson, R. P. (1996). Does the Beck Anxiety Inventory measure anything beyond panic attack symptoms? Behaviour Research and Therapy, 34, 949-954. Fydrich, T., Dowdall, D., & Chambless, D. L. (1992). Reliability and validity of the Beck Anxiety Inventory. Journal of Anxiety Disorders, 6, 55-61. Hamilton, M. (1959). The assessment of anxiety states by rating. British Journal of Medical Psychology, 32, 50-55. Riskind, J. H., Beck, A. T., Brown, G., & Steer, R. A. (1987). Taking the measure of anxiety and depression: validity of the reconstructed Hamilton scales. Journal of Nervous and Mental Disease, 175, 474-479. Spielberger, C. D. (1983). Manual for the State-Trait Anxiety Inventory (Form Y). Palo Alto, CA: Consulting Psychologists Press. Spitzer, R. L., Williams, J. B. W., Gibbon, M., & First, M. B. (1990). User's guide for the Structured Clinical Interview for DSM-III-R. Washington, DC: American Psychiatric Press. Taylor, S., Koch, W. J., & McNally, R. J. (1992). How does anxiety sensitivity vary across the anxiety disorders? Journal of Anxiety Disorders, 6, 249-259.
BRT34/lI-12--E