Behac Res. Ther. Vol. 30, No. 1, PP. 45-52, 1992
Printed in
Great Britain.
~3-7%7/92 $5.00+ 0.00
All rigtitsreserved
Copyright 0
1991
Pergamon Presspie
DIFFERENCES IN REPORTED SYMPTOM PROFILE BETWEEN PANIC DISORDER AND OTHER DSM-III-R ANXIETY DISORDERS RONALD M. RAPEE,‘* WILLIAMC. SANDERSON,~PAMELAA. MCCAULEY~ and PETER A. DI NARIIO~*~ ‘Departmentof Psychology, University of Queensland, Queensland 4072, Australia, *Departmentof Psychiatry, Albert Einstein College of Medicine, New York, N.Y., sCenter for Stress and Anxiety Disorders, State University of New York at Albany, Albany, N.Y. and 4Department of Psychology, State University of New York at Oneonta, Oneonta, N.Y., U.S.A.
Summary-Previous research has indicated that reports of panic attacks are associated with a different set of symptoms to reports of generalized anxiety. The present two studies attempted to extend these findings to specific (situational) fears, In Study 1, 55 subjects with panic disorder were compared on their symptom profile during their panic attacks to 65 subjects with other anxiety disorders [simple phobia, social phobia and ob~ive-compulsive disorder (OCD)] during response to their feared cue. The results indicated that, compared to subjects with other anxiety disorders, subjects with panic disorder were more likely to report parasthesias, dizziness, faintness, unreality, dyspnea, fear of dying and fear of going cr~y~losing control. In Study 2, 90 subjects meeting diagnostic criteria for both panic disorder and another anxiety disorder (simple phobia, social phobia or OCD) were compared on the symptoms experienced during their unexpected panic attacks and their situationally-t~ggered fears respectively. Combining the symptoms found in Study 1 to differ between the groups into a linear combination, there was a significant interaction found between the type of fear reaction (panic attack vs cued fear response) and symptom group. Taken together, these findings suggest that reports of unexpected panic attacks associated with panic disorder are characterized by a different symptom profile to reports of specific fear reactions that are part of a phobic disorder or OCD.
The question of whether panic attacks constitute a diagnostically unique phenomenon has produced considerable debate and investigation since the early 1960s (e.g. Klein, 1964). Phenomena meeting criteria for panic attacks appear to be experienced by a wide range of individuals. Some studies have indicated that approx. 35% of the normal population have experienced a panic attack in the last year (Norton, Harrison, Hausch 8 Rhodes, 1985). However, most of these panic attacks would be termed cued, or expected, since they typically occur in response to a specific cue or situation. Between 6% (in the past year) to 14% (ever) have experienced what could be described as an unexpected panic attack (Norton, Dorward & Cox, 1986; Rapee, Antis & Barlow, 1988). In addition, it has been demonstrated that the majority of patients suffering anxiety disorders other than panic disorder have experienced phenomena in their lives which meet DSM-III criteria for a panic attack (Barlow, Vermilyea, Blanchard, Vermilyea, Di Nardo & Cerny, 1985), although most would be categorized as expected attacks. Nevertheless, despite these findings suggesting that many individuals experience panic attacks, there are some suggestions that the unexpected panic attacks reported by individuals with panic disorder are distinct from fear and anxiety reported by individuals with other anxiety disorders. There have been numerous suggestions that panic attacks respond differently to medication than generalized or anticipator anxiety (Klein & Fink, 1962; McNair & Kahn, 1981). However, these data are questionable on methodological grounds and conclusive evidence of a differential drug response remains to be demonstrated (Margraf, Ehlers & Roth, 1986; Wilson, 1987). Individuals with panic disorder have been shown, through biological challenge tests, to respond to different cues than individuals with either generalized anxiety disorder or social phobia (Liebowitz, Fyer, Gorman, Dillon, Davies, Stein, Cohen & Klein, 1985; Rapee, 1986; Rapee, Mattick & Murrell, 1986). Finally, the subjective experience of panic attacks does appear to be different to that of generalized anxiety (Ande~on, Noyes & Crowe, 1984; Hibbert, 1984; Rapee, 1985). *Author for correspondence. 45
46
RONALD M. RAPEEet al.
In an earlier study of patients with various DSM-III anxiety disorders, Barlow et al. (1985) compared the experience of sudden bursts of fear (panic attacks) which were always cued by a specific stimulus with those which were less predictable. Overall, the results suggested that “ . . . more people with unpredictable panic report symptoms such as dizziness, parasthesias, shaking, pain in the chest, and fear of going crazy or loss of control” (p. 326). However, despite these suggestions, only dizziness and the cognitive symptoms emerged as significant discriminators between expected and unexpected panic. It is possible that more statistically significant results would have been found with a larger number of Ss, especially in the non-panic disorder group. Thus the aim of the present study was to compare the symptoms reported by panic disorder patients during their typical panic attacks with the symptoms reported by other anxiety disorder Ss upon exposure to their feared stimuli. STUDY
l-METHOD
Assessment Assessment was conducted through administration of a structured interview, the Anxiety Disorders Interview Schedule-Revised (ADIS-R) (Barlow, 1985; Di Nardo, O’Brien, Barlow, Waddell & Blanchard, 1983). According to the ADIS-R, Ss are assigned all anxiety disorder diagnoses for which they meet DSM-III-R criteria. Of the disorders which an individual has, one is then designated as the primary disorder and the rest as secondary disorders. At our clinic the primary disorder is that one which appears to produce most current distress and interference in an individual’s life (see Barlow, Di Nardo, Vermilyea, Vermilyea & Blanchard, 1986). While the reliability of the diagnoses made in the present sample cannot be calculated, recent research at our clinic has indicated that panic disorder with agoraphobia can be diagnosed reliably (rc = 0.79). Social phobia, obsessive-compulsive disorder, and simple phobias can also be diagnosed reliably (K = 0.86, 0.87, 0.92 respectively) (Di Nardo, Rapee, Moras & Barlow, 1991). The qualifications of interviewers for the present study were the same as for other studies at this center, i.e. clinical psychologists and graduate students with at least 1 yr’s experience with anxiety disorders and extensive training in the use of the ADIS-R. Subjects The Ss for this study were 120 patients assessed at the Phobia and Anxiety Disorders Clinic, State University of New York at Albany, who received one of the following primary diagnoses based on DSM-III-R criteria (American Psychiatric Association, 1987): Panic Disorder with Agoraphobia (n = 55: 24 with mild agoraphobic avoidance, 22 with moderate avoidance, and nine with severe avoidance), Simple Phobia (n = 18), Social Phobia (n = 32), and Obsessive-Compulsive Disorder (OCD) (n = 15); 71% (85/120) of the sample were females. The mean age of the sample was 34.6 yr (range 18-63 yr). There was no overlap between the present sample and samples used in previous classification studies in this center (e.g. Barlow et al., 1985, 1986; Di Nardo et al., 1983). Patients with current substance abuse, suicidal ideation, psychotic disorders, or organic brain problems, were excluded from the study. Procedure During the structured interview, patients were asked about the occurrence of any panic attacks. Specifically, patients were asked: “Have you had times when you felt a sudden rush of intense fear or anxiety or a feeling of impending doom ?” If patients answered yes, the interviewer would further question the patient to determine if the panic attacks occurred at unexpected times (i.e. not immediately upon exposure to a phobic situation) or if the symptoms only occurred in a specific situation (e.g. public speaking, heights, having an obsessive thought). Thus, the nature of this questioning was to establish if at least some panic attacks were unexpected or uncued (such as those associated with panic disorder with agoraphobia) or if the fear was always cued by a phobic stimulus (i.e. simple phobia), a social situation (i.e. social phobia), or by obsessive thoughts/compulsive behaviors (i.e. obsessive-compulsive disorder). Due to the nature of the questioning in the ADIS-R, a distinction was not made between uncued and unexpected attacks. Once the nature of the fear was determined, each patient was asked about the presence or absence
Symptom
profile
differences
47
and the degree of intensity of the 14 panic symptoms listed in the DSM-III-R. Each symptom was rated by the interviewer on a 5-point scale of severity (0 = absent, 4 = very severe). Symptom questioning was specific to each disorder in order to ascertain symptoms which were exclusive to that anxiety disorder. Specifically, panic disorder with agoraphobia patients were questioned “only for anxiety attacks which occur unexpectedly in a variety of situations” (ADIS-R, p. 3). Ratings were made of “each symptom which is typical of the most recent attacks . . .” (ADIS-R, p. 3). On the other hand, simple phobia patients were asked about the symptoms which typically occur when they encounter the phobic situation or object. Social phobia patients were asked about the symptoms which typically occur when they encounter a social situation. Finally, obsessive-compulsive disorder patients were asked about the symptoms they typically experience when they are having or resisting their specific obsessions or compulsions. While the interviewers were not blind to the diagnosis, the information was collected during routine initial assessment interviews. There were no specific hypotheses in our clinic about symptomatic differences between panic disorder and other anxiety disorder patients. RESULTS
Previous research on a large sample has demonstrated that no differences exist between the subtypes of panic disorder based upon extent of agoraphobic avoidance (mild, moderate, severe) in regard to the presence or severity of panic symptoms (Sanderson & Barlow, 1986). In order to confirm this finding, we compared the number of Ss in each subtype of panic disorder who reported each of the 14 panic disorder symptoms during their typical panic attacks using a chi-square analysis. There were no significant differences between any of the subtypes. Thus, these Ss were collapsed into one overall panic disorder group for the remainder of the analyses. The percentage of patients endorsing specific panic symptoms were compared between the 55 Ss meeting DSM-III-R criteria for a primary diagnosis of panic disorder (regardless of degree of avoidance) and the 65 Ss with a primary diagnosis of one of the other anxiety disorders. This two-group comparison will be the one presented here since the aim of the study was to compare panic disorder with other anxiety disorders. However, a chi-square analysis comparing the number of Ss reporting each of the DSM-III-R panic symptoms in the social phobia, simple phobia, and OCD groups indicated no significant differences. Table 1 presents the number of Ss in each category reporting each symptom (severity of one or more). Chi-square analyses were conducted for each symptom and a modified Bonferroni technique was used to adjust for experiment-wise alphas (Keppel, 1982). Based on this adjustment, the critical alpha was calculated to be 0.011. As can be seen in Table 1, there were significant differences (P < 0.01) on 7 of the 14 panic symptoms: fear of dying, fear of going crazy/losing control, parasthesias, dizziness, faintness, unreality, and dyspnea. In each of these cases, a higher Table I. Percentage of patients reporting specific panic symptoms in the panic disorder and other anxiety disorders groups DSM-III-R panic symptoms Cognitive symptoms Fear of dying Fear of going crazy/losing control Physical symptoms Parasthesias Dizziness Faintness Dyspnea Unreality Choking Hot/cold flushes Trembling Abdominal distress Chest pain Palpitations Sweating *P < 0.01.
Other anxiety disorders (n = 65)
x2
49.1 16.4
12.5 45.3
19.1’ 11.9’
51.4 87.3 61.3 14.5 56.4 49.1 15.5 85.5 56.4 38.2 87.3 69.1
16.9 41.1 33.8 44.6 21.1 24.6 55.4 69.2 46.0 29.2 80.0 61.1
21.2* 20.1’ 13.3’ 11.0* 10.1’ 7.8 5.1 4.4 1.3 1.1 1.1 0.0
Panic disorder with agoraphobia (n = 55)
48
RONALD
M. RAPEE~~
al.
percentage of panic disorder patients reported experiencing the symptom compared to the other three categories. The mean intensity of each sensation, for those Ss who reported the sensation, was compared across the four diagnostic groups using analysis of variance. Using a modified Bonferroni derived alpha of 0.01, there were no significant differences found between the groups on any of the symptoms. In order to make the results more meaningful, a ‘profile analysis’ was conducted examining the interaction between two linear combinations of symptoms in the two diagnostic groups. The first linear combination was the sum of the symptoms found above to differ between the two groups (i.e. fear of dying, fear of going crazy~losing control, parasthesias, dizziness, faintness, unreality, and dyspnea). The second linear combination was the sum of the remaining seven symptoms. Panic disorder patients reported a mean total of 4.2 (SD = 1.8) symptoms from group one while the other anxiety disorders reported a mean of 2.4 (SD = 2.0). Of the group two symptoms, panic disorder patients reported a mean of 4.4 (SD = 1.6) while the other anxiety disorder patients reported 3.8 (SD = 1.7). Using an analysis of variance, this constituted a significant interaction (F 1,107 = 11.67; P < 0.005). DISCUSSKON
According to the results of the first study, patients with a primary diagnosis of panic disorder seem to experience their panic attacks as qualitatively different phenomena than the fear or anxiety experienced by patients with social phobia, simple phobia, or OCD upon exposure to their feared stimuli. Specifically, panic attacks experienced by patients with panic disorder are more likely to include fears of dying or going cra~y/losing control, and the somatic sensations of parasthesias, dizziness, faintness, unreality, and dyspnea. These symptoms are very similar to those which appear to differ between cued and uncued panic attacks in the study by Barlow et al. (1985). The fact that only a subgroup of symptoms differed between the groups suggests that this difference is a qualitative rather than a quantitative one. This suggestion raises two possible interpretations. It may be that the difference lies within the individual. That is, panic disorder patients may be generally more likely to experience certain symptoms than patients with other anxiety disorders. Alternatively, it may be that the difference lies within the fear reaction itself, such that panic attacks which occur unexpectedly and without apparent cues, may be qualitatively different phenomena to panic or anxiety which is produced consistently upon exposure to an aversive stimulus. Thus, we decided to conduct a second study designed to answer this question by examining those indi~duals who met diagnostic criteria for both panic disorder and a specific phobic or obsessive-compuIsive disorder. STUDY
2-METHOD
Procedure
Patients in this study were selected from individuals who presented to the Phobia and Anxiety Disorders Clinic at the State University of New York at Albany for assessment and treatment. Assessment was conducted in the same manner as Study 1. Based on interview data using the ADIS-R, all patients were given a primary diagnosis and any secondary diagnoses which were applicable. The primary diagnosis was the DSM-III-R disorder which appeared to produce the greatest current distress andfor interference in the individual’s life. Secondary diagnoses referred to any other disorders for which the individual met diagnostic criteria but which appeared to have a lesser impact on their life (Barlow et al., 1986). In this second study, 90 patients were selected who met DSM-III-R diagnostic criteria for both panic disorder and either social phobia, simple phobia, or obsessive-compulsive disorder. Both diagnoses had to be rated by the diagnosing interviewer at a severity of at least three or more on a O-8 scaIe of distress~interferen~ (0 = no distress/interference, 8 = very severe distress/interference). The sample of Ss for Study 2 was only slightly overlapped with those used in Study 1 with 10 of 90 (I 1.1 *A) being common. Of the patients included in the study, 47 had a primary diagnosis of panic disorder with agoraphobia and a secondary diagnosis of social phobia, 26 had a primary diagnosis of panic disorder with
Symptom
49
profile differences
Table 2. Percentage of patients reporting each panic symptom during panic attacks and specific fears Symptom Cognitive symptoms Fear of dying Fear of going crazy/losing control Physical symptoms Parasthesias Dizziness Faintness Dyspnea Unreality Choking Hot/cold flushes Trembling Abdominal distress Chest pain Palpitations Sweating
Panic attack
Specific fear
y*
45.6 73.3
15.6 42.2
13.31 7.5’
48.9 83.3 67.8 63.3 57.8 34.4 73.3 74.4 61.1 44.4 82.2 70.0
20.0 63.3 42.2 42.2 38.9 22.2 65.8 67.8 38.9 23.3 72.2 68.9
10.9* 2.5 5.3 3.8 3.3 2.4 0.4 0.3 4.4 5.9 0.6 0.0
‘P
Printed in
Great Britain.
~3-7%7/92 $5.00+ 0.00
All rigtitsreserved
Copyright 0
1991
Pergamon Presspie
DIFFERENCES IN REPORTED SYMPTOM PROFILE BETWEEN PANIC DISORDER AND OTHER DSM-III-R ANXIETY DISORDERS RONALD M. RAPEE,‘* WILLIAMC. SANDERSON,~PAMELAA. MCCAULEY~ and PETER A. DI NARIIO~*~ ‘Departmentof Psychology, University of Queensland, Queensland 4072, Australia, *Departmentof Psychiatry, Albert Einstein College of Medicine, New York, N.Y., sCenter for Stress and Anxiety Disorders, State University of New York at Albany, Albany, N.Y. and 4Department of Psychology, State University of New York at Oneonta, Oneonta, N.Y., U.S.A.
Summary-Previous research has indicated that reports of panic attacks are associated with a different set of symptoms to reports of generalized anxiety. The present two studies attempted to extend these findings to specific (situational) fears, In Study 1, 55 subjects with panic disorder were compared on their symptom profile during their panic attacks to 65 subjects with other anxiety disorders [simple phobia, social phobia and ob~ive-compulsive disorder (OCD)] during response to their feared cue. The results indicated that, compared to subjects with other anxiety disorders, subjects with panic disorder were more likely to report parasthesias, dizziness, faintness, unreality, dyspnea, fear of dying and fear of going cr~y~losing control. In Study 2, 90 subjects meeting diagnostic criteria for both panic disorder and another anxiety disorder (simple phobia, social phobia or OCD) were compared on the symptoms experienced during their unexpected panic attacks and their situationally-t~ggered fears respectively. Combining the symptoms found in Study 1 to differ between the groups into a linear combination, there was a significant interaction found between the type of fear reaction (panic attack vs cued fear response) and symptom group. Taken together, these findings suggest that reports of unexpected panic attacks associated with panic disorder are characterized by a different symptom profile to reports of specific fear reactions that are part of a phobic disorder or OCD.
The question of whether panic attacks constitute a diagnostically unique phenomenon has produced considerable debate and investigation since the early 1960s (e.g. Klein, 1964). Phenomena meeting criteria for panic attacks appear to be experienced by a wide range of individuals. Some studies have indicated that approx. 35% of the normal population have experienced a panic attack in the last year (Norton, Harrison, Hausch 8 Rhodes, 1985). However, most of these panic attacks would be termed cued, or expected, since they typically occur in response to a specific cue or situation. Between 6% (in the past year) to 14% (ever) have experienced what could be described as an unexpected panic attack (Norton, Dorward & Cox, 1986; Rapee, Antis & Barlow, 1988). In addition, it has been demonstrated that the majority of patients suffering anxiety disorders other than panic disorder have experienced phenomena in their lives which meet DSM-III criteria for a panic attack (Barlow, Vermilyea, Blanchard, Vermilyea, Di Nardo & Cerny, 1985), although most would be categorized as expected attacks. Nevertheless, despite these findings suggesting that many individuals experience panic attacks, there are some suggestions that the unexpected panic attacks reported by individuals with panic disorder are distinct from fear and anxiety reported by individuals with other anxiety disorders. There have been numerous suggestions that panic attacks respond differently to medication than generalized or anticipator anxiety (Klein & Fink, 1962; McNair & Kahn, 1981). However, these data are questionable on methodological grounds and conclusive evidence of a differential drug response remains to be demonstrated (Margraf, Ehlers & Roth, 1986; Wilson, 1987). Individuals with panic disorder have been shown, through biological challenge tests, to respond to different cues than individuals with either generalized anxiety disorder or social phobia (Liebowitz, Fyer, Gorman, Dillon, Davies, Stein, Cohen & Klein, 1985; Rapee, 1986; Rapee, Mattick & Murrell, 1986). Finally, the subjective experience of panic attacks does appear to be different to that of generalized anxiety (Ande~on, Noyes & Crowe, 1984; Hibbert, 1984; Rapee, 1985). *Author for correspondence. 45
46
RONALD M. RAPEEet al.
In an earlier study of patients with various DSM-III anxiety disorders, Barlow et al. (1985) compared the experience of sudden bursts of fear (panic attacks) which were always cued by a specific stimulus with those which were less predictable. Overall, the results suggested that “ . . . more people with unpredictable panic report symptoms such as dizziness, parasthesias, shaking, pain in the chest, and fear of going crazy or loss of control” (p. 326). However, despite these suggestions, only dizziness and the cognitive symptoms emerged as significant discriminators between expected and unexpected panic. It is possible that more statistically significant results would have been found with a larger number of Ss, especially in the non-panic disorder group. Thus the aim of the present study was to compare the symptoms reported by panic disorder patients during their typical panic attacks with the symptoms reported by other anxiety disorder Ss upon exposure to their feared stimuli. STUDY
l-METHOD
Assessment Assessment was conducted through administration of a structured interview, the Anxiety Disorders Interview Schedule-Revised (ADIS-R) (Barlow, 1985; Di Nardo, O’Brien, Barlow, Waddell & Blanchard, 1983). According to the ADIS-R, Ss are assigned all anxiety disorder diagnoses for which they meet DSM-III-R criteria. Of the disorders which an individual has, one is then designated as the primary disorder and the rest as secondary disorders. At our clinic the primary disorder is that one which appears to produce most current distress and interference in an individual’s life (see Barlow, Di Nardo, Vermilyea, Vermilyea & Blanchard, 1986). While the reliability of the diagnoses made in the present sample cannot be calculated, recent research at our clinic has indicated that panic disorder with agoraphobia can be diagnosed reliably (rc = 0.79). Social phobia, obsessive-compulsive disorder, and simple phobias can also be diagnosed reliably (K = 0.86, 0.87, 0.92 respectively) (Di Nardo, Rapee, Moras & Barlow, 1991). The qualifications of interviewers for the present study were the same as for other studies at this center, i.e. clinical psychologists and graduate students with at least 1 yr’s experience with anxiety disorders and extensive training in the use of the ADIS-R. Subjects The Ss for this study were 120 patients assessed at the Phobia and Anxiety Disorders Clinic, State University of New York at Albany, who received one of the following primary diagnoses based on DSM-III-R criteria (American Psychiatric Association, 1987): Panic Disorder with Agoraphobia (n = 55: 24 with mild agoraphobic avoidance, 22 with moderate avoidance, and nine with severe avoidance), Simple Phobia (n = 18), Social Phobia (n = 32), and Obsessive-Compulsive Disorder (OCD) (n = 15); 71% (85/120) of the sample were females. The mean age of the sample was 34.6 yr (range 18-63 yr). There was no overlap between the present sample and samples used in previous classification studies in this center (e.g. Barlow et al., 1985, 1986; Di Nardo et al., 1983). Patients with current substance abuse, suicidal ideation, psychotic disorders, or organic brain problems, were excluded from the study. Procedure During the structured interview, patients were asked about the occurrence of any panic attacks. Specifically, patients were asked: “Have you had times when you felt a sudden rush of intense fear or anxiety or a feeling of impending doom ?” If patients answered yes, the interviewer would further question the patient to determine if the panic attacks occurred at unexpected times (i.e. not immediately upon exposure to a phobic situation) or if the symptoms only occurred in a specific situation (e.g. public speaking, heights, having an obsessive thought). Thus, the nature of this questioning was to establish if at least some panic attacks were unexpected or uncued (such as those associated with panic disorder with agoraphobia) or if the fear was always cued by a phobic stimulus (i.e. simple phobia), a social situation (i.e. social phobia), or by obsessive thoughts/compulsive behaviors (i.e. obsessive-compulsive disorder). Due to the nature of the questioning in the ADIS-R, a distinction was not made between uncued and unexpected attacks. Once the nature of the fear was determined, each patient was asked about the presence or absence
Symptom
profile
differences
47
and the degree of intensity of the 14 panic symptoms listed in the DSM-III-R. Each symptom was rated by the interviewer on a 5-point scale of severity (0 = absent, 4 = very severe). Symptom questioning was specific to each disorder in order to ascertain symptoms which were exclusive to that anxiety disorder. Specifically, panic disorder with agoraphobia patients were questioned “only for anxiety attacks which occur unexpectedly in a variety of situations” (ADIS-R, p. 3). Ratings were made of “each symptom which is typical of the most recent attacks . . .” (ADIS-R, p. 3). On the other hand, simple phobia patients were asked about the symptoms which typically occur when they encounter the phobic situation or object. Social phobia patients were asked about the symptoms which typically occur when they encounter a social situation. Finally, obsessive-compulsive disorder patients were asked about the symptoms they typically experience when they are having or resisting their specific obsessions or compulsions. While the interviewers were not blind to the diagnosis, the information was collected during routine initial assessment interviews. There were no specific hypotheses in our clinic about symptomatic differences between panic disorder and other anxiety disorder patients. RESULTS
Previous research on a large sample has demonstrated that no differences exist between the subtypes of panic disorder based upon extent of agoraphobic avoidance (mild, moderate, severe) in regard to the presence or severity of panic symptoms (Sanderson & Barlow, 1986). In order to confirm this finding, we compared the number of Ss in each subtype of panic disorder who reported each of the 14 panic disorder symptoms during their typical panic attacks using a chi-square analysis. There were no significant differences between any of the subtypes. Thus, these Ss were collapsed into one overall panic disorder group for the remainder of the analyses. The percentage of patients endorsing specific panic symptoms were compared between the 55 Ss meeting DSM-III-R criteria for a primary diagnosis of panic disorder (regardless of degree of avoidance) and the 65 Ss with a primary diagnosis of one of the other anxiety disorders. This two-group comparison will be the one presented here since the aim of the study was to compare panic disorder with other anxiety disorders. However, a chi-square analysis comparing the number of Ss reporting each of the DSM-III-R panic symptoms in the social phobia, simple phobia, and OCD groups indicated no significant differences. Table 1 presents the number of Ss in each category reporting each symptom (severity of one or more). Chi-square analyses were conducted for each symptom and a modified Bonferroni technique was used to adjust for experiment-wise alphas (Keppel, 1982). Based on this adjustment, the critical alpha was calculated to be 0.011. As can be seen in Table 1, there were significant differences (P < 0.01) on 7 of the 14 panic symptoms: fear of dying, fear of going crazy/losing control, parasthesias, dizziness, faintness, unreality, and dyspnea. In each of these cases, a higher Table I. Percentage of patients reporting specific panic symptoms in the panic disorder and other anxiety disorders groups DSM-III-R panic symptoms Cognitive symptoms Fear of dying Fear of going crazy/losing control Physical symptoms Parasthesias Dizziness Faintness Dyspnea Unreality Choking Hot/cold flushes Trembling Abdominal distress Chest pain Palpitations Sweating *P < 0.01.
Other anxiety disorders (n = 65)
x2
49.1 16.4
12.5 45.3
19.1’ 11.9’
51.4 87.3 61.3 14.5 56.4 49.1 15.5 85.5 56.4 38.2 87.3 69.1
16.9 41.1 33.8 44.6 21.1 24.6 55.4 69.2 46.0 29.2 80.0 61.1
21.2* 20.1’ 13.3’ 11.0* 10.1’ 7.8 5.1 4.4 1.3 1.1 1.1 0.0
Panic disorder with agoraphobia (n = 55)
48
RONALD
M. RAPEE~~
al.
percentage of panic disorder patients reported experiencing the symptom compared to the other three categories. The mean intensity of each sensation, for those Ss who reported the sensation, was compared across the four diagnostic groups using analysis of variance. Using a modified Bonferroni derived alpha of 0.01, there were no significant differences found between the groups on any of the symptoms. In order to make the results more meaningful, a ‘profile analysis’ was conducted examining the interaction between two linear combinations of symptoms in the two diagnostic groups. The first linear combination was the sum of the symptoms found above to differ between the two groups (i.e. fear of dying, fear of going crazy~losing control, parasthesias, dizziness, faintness, unreality, and dyspnea). The second linear combination was the sum of the remaining seven symptoms. Panic disorder patients reported a mean total of 4.2 (SD = 1.8) symptoms from group one while the other anxiety disorders reported a mean of 2.4 (SD = 2.0). Of the group two symptoms, panic disorder patients reported a mean of 4.4 (SD = 1.6) while the other anxiety disorder patients reported 3.8 (SD = 1.7). Using an analysis of variance, this constituted a significant interaction (F 1,107 = 11.67; P < 0.005). DISCUSSKON
According to the results of the first study, patients with a primary diagnosis of panic disorder seem to experience their panic attacks as qualitatively different phenomena than the fear or anxiety experienced by patients with social phobia, simple phobia, or OCD upon exposure to their feared stimuli. Specifically, panic attacks experienced by patients with panic disorder are more likely to include fears of dying or going cra~y/losing control, and the somatic sensations of parasthesias, dizziness, faintness, unreality, and dyspnea. These symptoms are very similar to those which appear to differ between cued and uncued panic attacks in the study by Barlow et al. (1985). The fact that only a subgroup of symptoms differed between the groups suggests that this difference is a qualitative rather than a quantitative one. This suggestion raises two possible interpretations. It may be that the difference lies within the individual. That is, panic disorder patients may be generally more likely to experience certain symptoms than patients with other anxiety disorders. Alternatively, it may be that the difference lies within the fear reaction itself, such that panic attacks which occur unexpectedly and without apparent cues, may be qualitatively different phenomena to panic or anxiety which is produced consistently upon exposure to an aversive stimulus. Thus, we decided to conduct a second study designed to answer this question by examining those indi~duals who met diagnostic criteria for both panic disorder and a specific phobic or obsessive-compuIsive disorder. STUDY
2-METHOD
Procedure
Patients in this study were selected from individuals who presented to the Phobia and Anxiety Disorders Clinic at the State University of New York at Albany for assessment and treatment. Assessment was conducted in the same manner as Study 1. Based on interview data using the ADIS-R, all patients were given a primary diagnosis and any secondary diagnoses which were applicable. The primary diagnosis was the DSM-III-R disorder which appeared to produce the greatest current distress andfor interference in the individual’s life. Secondary diagnoses referred to any other disorders for which the individual met diagnostic criteria but which appeared to have a lesser impact on their life (Barlow et al., 1986). In this second study, 90 patients were selected who met DSM-III-R diagnostic criteria for both panic disorder and either social phobia, simple phobia, or obsessive-compulsive disorder. Both diagnoses had to be rated by the diagnosing interviewer at a severity of at least three or more on a O-8 scaIe of distress~interferen~ (0 = no distress/interference, 8 = very severe distress/interference). The sample of Ss for Study 2 was only slightly overlapped with those used in Study 1 with 10 of 90 (I 1.1 *A) being common. Of the patients included in the study, 47 had a primary diagnosis of panic disorder with agoraphobia and a secondary diagnosis of social phobia, 26 had a primary diagnosis of panic disorder with
Symptom
49
profile differences
Table 2. Percentage of patients reporting each panic symptom during panic attacks and specific fears Symptom Cognitive symptoms Fear of dying Fear of going crazy/losing control Physical symptoms Parasthesias Dizziness Faintness Dyspnea Unreality Choking Hot/cold flushes Trembling Abdominal distress Chest pain Palpitations Sweating
Panic attack
Specific fear
y*
45.6 73.3
15.6 42.2
13.31 7.5’
48.9 83.3 67.8 63.3 57.8 34.4 73.3 74.4 61.1 44.4 82.2 70.0
20.0 63.3 42.2 42.2 38.9 22.2 65.8 67.8 38.9 23.3 72.2 68.9
10.9* 2.5 5.3 3.8 3.3 2.4 0.4 0.3 4.4 5.9 0.6 0.0
‘P
