A community survey of panic

Journal oJ~Am,en, Disorders. Vol. 2. pp. 157- 167. 1988 Printed in the USA. All nghts reserved.

A Community RHONDA

Copynghr

0887-6185.88 53.00 + .W C 1988 Pergamon Pres pit

Survey of Panic

A. SALGE, B.S., J. GAYLE BECK, ANN C. LOGAN, B.A.

PH.D.,

AND

University of Houston

Abstract-This study examined the prevalence of panic attacks among 410 residents of the greater Houston metropolitan area. Subjects were contacted by telephone using random digit dialing, and surveyed using a structured interview. Respondents were categorized into frequent, infrequent, and non-panic groups. Subjects who met the DSM-III criteria of at least three panic attacks within a three-week interval, including 4 of 12 symptoms during a typical attack, comprised the frequent panic (Panic Disorder) group. Infrequent panickers reported fewer than three panic attacks within a three-week interval with 4 of 12 symptoms during a typical attack. Results revealed one-year prevalence rates of .8% for subjects reporting frequent panic attacks, 14.1% for infrequent panickers. and 85.1% for non-panickers. Subject perceptions of the definition and frequency of panic were assessed, demonstrating a considerable lack of knowledge of what constitutes a panic attack. Additionally, infrequent panickers estimated a significantly higher prevalence of panic in the public than non-panickers. Presumed precipitating factors, post-panic coping reactions, and panic attacks in household members (including children) were reported. Implications for understanding etiologic factors in Panic Disorder are discussed.

Recent reformulations of the anxiety disorders have resulted in an integration of panic disorder and agoraphobia within DSM-III-R, suggesting that these two disorders may be part of the same clinical syndrome. This viewpoint has been expressed in several recent conceptual reviews which suggest that cognitive models can explain both fear of unpredictable anxiety attacks, which is common in panic disorder, and generalized avoidance behavior, a hallmark of agoraphobia (Barlow, 1986; Beck & Emery, 1985; Clark, 1986; Margraf, Ehlers, & Roth, 1986). By these accounts, negative cognitive appraisals of physical sensations, such as palpitations, breathlessness, and dizziness, contribute to the perception of threat, a defining feature of both of these disorders. HypothetiThis study was conducted by the first author in partial fulfillment of the requirements for University Honors at the University of Houston. The authors wish to thank Dr. John Vincent and Dr. Darryl Dobbs for their ,,jistance on the honors committee. Support for this project was protiided. in part, by a gr_.it from the American Heart Association, Texas Affiliate (#86Ci-491) to the second author. Address corresp*&ence snd reltirnt requests to J. GayI? Beck, Ph.D., Department of Psychology, University of fiouston, rJouston, TX 77004. 157

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SALGE,

J. G.

BECK,

AND

A.

C.

LOGAN

tally, these negative appraisals initiate fear and apprehension, particularly concerning the possibility of panic re-occurring. and motivate avoidance of situations where panic could be triggered. To date, research supporting a unitary perspective of these syndromes is limited and had tended to rely on comparisons of separate samples of agoraphobics and panic-disordered individuals. For example, Hallam (1978) concluded in a review of the literature, that agoraphobia is a feature of related anxiety states, rather than a separate diagnostic entity. Support for this conclusion comes from Hallam’s observation that patients with both types of disorders share anxiety and phobic symptoms and have common etiological features. Sheehan, Sheehan, and Minichiello (1981) have similarly reported that the onset of panic frequently precedes development of phobic avoidance by three to six months, suggesting a continuum in the natural history of these anxiety disorders. By these accounts, agoraphobia is a form of avoidance that is conditioned by the occurrence of unpredictable and unexplained panic. A recent comparison of 82 patients with panic disorder (Noyes, Clancy, Garvey, & Anderson, 1987) suggests that little difference exists in clinical features between patients with no avoidance, limited avoidance, or extensive avoidance. In this study, patients without avoidance had a later onset, more frequent remissions, and milder symptoms, relative to patients to agoraphobia. To date. the presumed progression of anxiety disorders has received support from one longitudinal investigation utilizing retrospective life charting techniques (Uhde et al., 1985). If the unitary model of anxiety disorders is indeed accurate, greater information on subclinical precursers could prove useful for understanding the progression from panic to phobic avoidance, as well as lending direction to preventative efforts. One approach for identifying these precursers is the epidemiological study. In the most complete study of this type, rates of 0.6%, 1.O%, and 0.9% for panic disorder were reported in New Haven, Baltimore, and St. Louis, respectively (Myers et al., 1984). These data were gathered using face-to-face interviews, with the Diagnostic Interview Schedule (DIS), which may overestimate the clinical severity of symptom reports (Anthony et al., 1985). Given this, it is possible that a number of individuals exist in the community with infrequent or mild anxiety symptoms who never seek professional help, yet manifest the early stages of an anxiety disorder. In a telephone survey study (Pollard & Henderson, in press), a prevalence rate of 2.8% was reported for agoraphobia with panic, a finding consistent with studies using clinical diagnoses (Myers et al., 1984). Given the hypothesized role of panic within the unitary perspective of anxiety disorders, the phenomenon of infrequent panic attacks appears relevant as a possible early manifestation of panic disorder. While numerous authors have noted the prevalence of individuals with infrequent panic attacks in a variety of medical services (e.g., Evans & Lum, 1977; Katon, 1984; Magarian, 1982), there has been little direct investigation of individuals with infrequent panic in the community. In one study of in-

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frequent panic. Norton, Harrison, Hauch, and Rhodes (1985) indicated that 34% of a sample of 186 college students had experienced at least one panic attack. A related comparison of individuals with panic disorder and infrequent panic suggests differences in physiological reactivity and awareness of panic-related autonomic sensations between these samples (Beck & Scott, 1987). Taken together, these studies suggest that infrequent panic may be common in the community at large and that closer examination of these individuals is warranted. The present investigation was designed to survey the general population of a large metropolitan community (Houston, Texas) to determine in a preliminary fashion the prevalence of panic disorder and infrequent panic. While face-to-face clinical interviews are preferable in this type of investigation, structured interviews conducted by telephone on a large scale can provide useful and valid information concerning the presence and frequency of psychiatric states within the community (Frey, 1983). Research examining the validity of responses in telephone interviews indicates that comparative responses are obtained with telephone and personal interviews on reports of embarrassing events (e.g., bankruptcy, arrests for drunken driving) and sensitive issues (e.g., abortion, alcohol consumption) (Groves. 1979). No direct comparison of these two methods is available for reports of psychiatric symptomatology. Community members were contacted by telephone using random digit dialing and categorized into frequent (panic disorder), infrequent, and non-panic groups. One year prevalence of panic was determined, as well as subject perceptions of the definition and everyday occurrence of panic attacks, presumed antecedent events, post-panic reactions, and reporting of panic in household members. METHOD Subjects Four hundred and ten (410) subjects participated in this investigation, of which 145 were male and 265 were female. Subject ages ranged from 18 to 8.5 years, and all were residents of the greater Houston metropolitan area. Instrumentation A questionnaire was developed to focus on four salient areas: prevalence of panic as determined by DSM-III criteria (American Psychiatric Association, 1980); subject perceptions of the definition and prevalence of panic attacks; antecedent factors and post-panic coping reactions; and prevalence of panic in household members of subjects. The first section of the questionnaire assessed the presence and frequency of panic attacks in participating subjects with no mention of

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LOGAN

DSM-III criteria. Subjects reporting panic attacks were asked to describe the episode to provide data on their perception of the nature of panic. At this point, the following description of panic attacks (derived from DSMIII) was introduced: A panic attack has been defined by the American Psychiatric Association as the sudden onset of intense fear or terror, often associated with feelings of fear of dying, going crazy, or doing something uncontrollable. Some of the most common symptoms during an attack are dizziness, difficulty breathing. chest pain, trembling, sweating, hot and cold flashes, choking sensations, and tingling in hands or feet. To follow these guidelines, you need to have had at least four of these symptoms during an attack.

Subjects then were asked whether they had experienced one or more panic attacks within the last year based on the DSM-III description. Responses to this question formed the basis of delineating subjects into frequent (three or more panic attacks within a three-week interval), infrequent (fewer than three panic attacks within the three-week interval preceding the phone contact, but at least one attack in the last year), and non-panic groups. The second section of the que.stionnaire was administered only to subjects reporting panic attacks. Subjects were asked whether their panic attacks were related to specific antecedents. Those responding affirmatively were asked to indicate applicable situations from the following list: job difficulties, health problems, problems with spouse or significant other, financial difficulties, and other. Subjects were then given a list of post-panic coping reactions such as seeking medical help or psychological help, confiding in a spouse or friend, ignoring the panic attack, avoiding the situation where the attack occurred, relaxation, using tranquilizers or other substances, and other. Subjects were asked to indicate all of the coping mechanisms they had employed. In the final section administered to all subjects. perceptions of the prevalence of panic in the general population and incidence of panic attacks in household members were surveyed, along with demographic data. The questionnaire was administered by two trained female experimenters. Procedure

The method of contacting subjects was based on telephone survey methodology (Frey, 1983). The original specifications for this investiga5,000 phone tion called for the random samplin g of approximately numbers to interview household residents 18 years or older, in order to obtain at least 1,000 completed interviews. Due to the difficulty associated with obtaining completed interviews, 1.991 calls were made. yielding a final N of 410 subjects. Each telephone number was dialed up to three times, and the adult who answered the phone was interviewed. If

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the household was not reached, the number was discarded from the investigation. The completion rate (number of completed interviews divided by the total number of subjects) was 20.6%. The response rate, which includes those eligible but unable to participate (non-English speaking, hard of hearing), refusals, and those who could not be reached, was 39.6%. Of all numbers called, 30.9% were either disconnected or recently unlisted. Calls that were placed to businesses (8.9%) were excluded. Subjects were contacted weekday evenings. Saturday mornings and afternoons, and Sunday evenings, during a six-month interval. Sampling In order to obtain a stratified random sample of the greater Houston metropolitan area, random digit dialing (RDD) with aid of the telephone directory was used (Sudman, 1976). This technique corrects for unequal selection probabilities, specifically the 20% of Americans who have unlisted telephone numbers. The directory was randomly sampled to determine the prefix (Central Office Code) and the first two digits of each number. The last two digits of each number were discarded and replaced by two randomly generated digits. This not only insured the anonymity of all subjects, but provided a sample representative of the number of unlisted telephone numbers within the respective COCs of the 410 subjects. The percentage of unlisted numbers was 12.7%. Additionally, the numbers selected from the directory were chosen at an interval of every 160th listing. This interval was determined by dividing the total number of listings in the directory by 5,000 (the original number to be sampled). A change in the number to be sampled to 1,991 did not present a methodological confound because the last two digits of each number were dropped; therefore, the sampling did not proceed alphabetically. Sampling within households was not random, as the adult who answered the phone was interviewed, rather than employing a randomized sampling procedure such as systematic random sampling (Friedman, 1980) or the Kish grid method (Groves, 1979). Additionally, it is recognized that individuals with psychiatric disorders might be easier to contact by phone, relative to those without psychiatric impairment. This potential sampling error was minimized by placing calls at times which maximized the likelihood of all subjects responding (Frey, 1983). However, the data derived from these sampling procedures should be regarded as preliminary given these potential confounds. RESULTS Subject Characteristics Of the 410 subjects interviewed, 64.6% were female and 35.4% were male. Mean age for the entire sample was 38.9 years (SD = 15.7). The

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AND A. C. LOGAN

greatest number of subjects resided in the southwest area (35.8%), with the remaining dispersed throughout the northwest (29.5%), southeast (19.3%), northeast (11.2%) and downtown (4.2%) areas. This distribution reflects density patterns in the city. Occupations of each subject were coded using the Hollingshead TwoFactor Index (Hollingshead & Redlich, 1958). The distribution of subjects across occupational level categories was: Level I, N = 16 (2.9%); Level II, N = 58 (14.1%); Level III, N = 68 (16.6%); Level IV, N = 53 (13%); Level V, N = 34 (8.3%); Level VI, N = 78 (19%); Level VII, N = 7 (1.7%); and students, unemployed and retired persons, N = 9.5 (23.2%). Prevalence

Rates (One-year)

Subjects were grouped into three categories: frequent panickers, infrequent panickers, and non-panickers. Prevalence figures along with related demographic data for each group are summarized in Table 1. Sub-

PREVALENCE RATES

(AND

Frequent Panickers (n = 30) Frequency of panic .8% (3) Prevalence of Panic by Sex: 0% (0) Male (n = 145) Female (n = 265) 1.1% (3) 38.3 Mean age

TABLE I Ns) WITH RELATED DEMOGRAPHICDATA Infrequent Panickers (n = 58)

NonPanickers (n = 349)

14.1% (58)

85% (349)

11.0% (16) 15.8% (42) 35.54

88.9% (129) 83.0% (220) 39.57

Total Sample (N = 410)

(410) 35.4% 64.6% 38.9

Occupation Level (Percentage by group)

I 2 3 4 5 6 7 0” Location: Northwest Northeast Southwest Southeast Downtown

(0) (0) (0) (0) 33.3% (1) 66.6% (2) (0) (0)

(0) 33.3% (I) 33.3% (I) 33.3% (I) (0)

1.7% 13.8% 12.1% 20.7% 10.3% 17.2%

(0) 22.4% (13)

4.3% 14.3% 17.5% 11.7% 7.7% 18.9% 2.0% 23.5%

(15) (50) (61) (41) (27) (66) (7) (82)

3.9% 14.2% 16.6% 12.9% 8.3% 19.0% 1.7% 23.2%

(16) (58) (68) (53) (34) (78) (7) (95)

22.4% 10.3% 41.4% 22.4% 3.4%

30.8 11.2% 34.9% 18.6% 4.3%

(108) (39) (122) (65) (IS)

29.5% I I .2% 35.8% 19.3% 4.2%

(121) (46) (147) (79) (17)

’ Oneinfrequent panicker refused lo divulge occupational level. b Occupational level 0 includes students, retirees. and unemployed.

(I)” (8) (7) (12) (6) (IO)

(13) (6) (24) (13) (2)

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jects reporting no panic attacks within the last year totalled 349 (85.1%). Of the remaining subjects, three (.8%) reported frequent panic attacks and 58 (14.1%) indicated infrequent panic attacks. Given the small size of the frequent panic group, it was excluded from statistical analysis. Group Differences

Infrequent panickers and non-panickers were compared along several dimensions. A chi-square test revealed that the groups did not differ significantly in distribution of sex (x2 = 2.18, n.s.). However, a significant age difference was found (t = 2.88, p < .Ol), with the infrequent panic sample being younger than the non-panickers. Chi-square analyses of occupation and location revealed no significant differences between infrequent and non-panickers. Situational Attributions

Fifty-one (83.6%) of all panickers (frequent and infrequent) reported that a situation or event played a part in triggering their panic attacks. Situation attributes are shown in Table 2. The “other” category included responses such as “lost dog, dreams, religious issues, and car trouble.” Post Panic Coping Reactions

Post panic coping reactions of all panickers (frequent and infrequent) were surveyed with an eight item question including an “other” category. Subjects were asked to indicate if they had used one or more coping reactions following an attack. As can be seen in Table 2, the most frequent response was to confide in a spouse or friend, reported by 55 panickers (90. I%), followed by ignoring the attack (39.3%), avoiding the situation where panic occurred (34.4%), seeking medical help (29.5%), use of tranquilizers or drugs (22.9%), seeking psychological help (21.3%), and other (21.3%). Among the responses in the “other” category were taking a hot bath, rationalization, screaming, and taking a long walk. Panic in Household

Members

Of all subjects interviewed, 74 (18%) reported knowledge of a household member(s) experiencing one or more panic attacks within the previous year. The number of infrequent (24) and non-panic (48) reporters were compared using a chi-square test which revealed a significant difference (x2 = 28.03, p < .Ol) indicating non-panickers had a higher incidence of reporting panic in others relative to infrequent panickers. A total of 93 household members of subjects were reported to have experienced panic attacks. Of this group, 42 were males and 51 were females. Interestingly, 24 (26%) were children under the age of 18 years. Subjects re-

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C. LOGAN

TABLE 2 ANTECEDENT FACTORS AND POST-PANICCOPINGREACTIONS Infrequent Panickers n = 49” Antecedent Factors: Job related Health related Problems with spouse or significant other Financial problems Other

Post Panic Coping Reactions: Confide in spouse or friend Ignore the panic attack Avoid situation where panic occurred Sought medical help Relaxation Took tranquilizers or drugs Sought psychological help Other

18 17 17

Frequent Panickers n = 2”

Total Sample iv = 51

I

19 (31%) 19 (31%) 19 (3 1%)

2 2

I9 20

I

Infrequent Panickers n = 58

Frequent Panickers n=3

1

3 I

52

23 20

I

16 17 I3 II II

Now. Totals exceed 100% because of multiple response format. a Ten subjects felt their panic attacks were not related to antecedent pated in this question set.

2

1 I 2 2 situational

factors: therefore.

20 (33%) 21 (34%) Total Sample A: = 61

55 (90.1%) 24 (39.3%) 21 (34.4%) I8 (29.5%) I8 (29.5%) 14 (22.9%) 13 (21.3%) I3 (21.3%) only 51 subjcc:s

partxi-

ported that 12 (12.9%) of the 93 household members who experienced panic attacks were frequent panickers (three or more panic attacks within a three-week period). Perceptions

All subjects were asked to give an estimate of how many people in a random group of 100 they believed had ever experienced a panic attack. The difference between group means was significant (t = 150.28, p < .OOl) for infrequent (F = 59.6) and non-panic (Z = 27.8) groups, indicating that infrequent panickers believed the lifetime prevalence of panic attacks to be higher than did non-panickers. Before the DSM-III definition of a panic attack was revealed to them, subjects were asked the following question, “Based on what you think a panic attack is, have you experienced a panic attack within the last year?” The 66 subjects (16%) who responded yes to the question were asked to give a description of a panic attack. Of this group, 12 subjects

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(18.2%) (81.8%) continue as if my

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gave a description which matched the DSM-III criteria, and 54 gave non-matching descriptions, including “unwillingness to an errand, urinating frequently, freezing. angry mood, or feeling mind goes blank.” DISCUSSION

The present investigation examined prevalence of panic within the preceding year in a major metropolitan community using DSM-III criteria. The prevalence rate found in this study for panic disorder (8%) is consistent with epidemiological estimates (Myers et al., 1984). However, according to secondhand subject accounts, 12.9% of household members experience frequent and severe attacks. Because these data are not derived from interviews, they must be interpreted with caution. This discrepancy suggests, however, that individuals perceive panic attacks in others more often than they experience these attacks themselves. Estimates for both infrequent and non-panic groups of the lifetime prevalence of panic attacks in the general public were considerably higher than actual findings to date. The potential limitations of this study stem from reliance on telephone interview methodology. Non-verbal facial cues and body gestures, which can add to the validity of diagnostic classification, are not obtained using this approach. Additionally, it is probable that a number of subjects did not feel comfortable disclosing their psychiatric symptoms to a stranger on the telephone. Without specific comparison of telephone and face-toface interview formats in psychiatric diagnosis, the impact of the methodology used in this study is difficult to determine. However, studies comparing these two formats in the assessment of embarrassing and sensitive events have shown negligible differences. Since the present investigation did not screen for comorbidity of diagnoses, it is also possible that subjects included in the study may carry a primary diagnosis other than panic disorder (Barlow et al, 1985). Overall, however, the telephone structured interview served as an efficient means of assessing in a preliminary fashion the occurrence of panic attacks in the population at large. Data from this study suggest that a sizable number of individuals in the community experience infrequent panic attacks (14.1%). While these subjects might not be diagnosed clinically using other interview measures (DIS), the fact is, they are reporting anxiety symptoms that appear to be at a subclinical level. Particularly striking are the post-panic coping reactions of subjects in the infrequent panic group, characterized by 31.4% avoiding the panic situation (conditioned avoidance of panic or threatening situation), and 70.3% using drugs or seeking medical and psychological help. This chain of behavior could indicate an early stage in the development of clinical anxiety disorders and potentially supports the notion that generalized avoidance behavior, as seen in agoraphobia, can be a sequelae to spontaneous, unpredictable panic attacks. Prospective longitudinal studies are necessary to confirm these speculations.

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C. LOGAN

Of the situational events reported by infrequent and frequent panickers in this study, no one antecedent factor emerged as salient in the etiology of panic, although approximately 30% of these subjects disclosed that they had experienced each of the following: job difficulties, health problems, problems with spouse or significant other, financial difficulties, or other factors. Whether or not environmental stressors are significant precipitating factors in the etiology of panic remains to be determined empirically. However, based on these data, it is apparent that individuals tend to attribute a relationship between stressful life events and panic attacks. Examination of subject perceptions of panic revealed that the majority of subjects (88.2%) queried on the definition of panic provided inaccurate descriptions. This was accompanied by over-identification of panic when an individual was experiencing another emotional state (e.g., anger). This general lack of knowledge about panic could potentially compound maladaptive reactions following the occurrence of anxiety. For example, insufficient information may lead to ineffective action such as avoidance, medication use, or attempts to identify a medical cause for panic in individuals with infrequent panic attacks. Overall, data reported in this study are suggestive of a relationship between panic and avoidance at an early subclinical stage. Based on these data, current conceptual models of the anxiety disorders appear to deserve elaboration, with greater emphasis on subclinical precursers in the etiology of severe anxiety. REFERENCES American Psychiatric Association (1980). Dingnostic and srarisrical manual of mental disorders (3rd ed.). Washington, DC: Author. Anthony, J. C., Folstein, M., Romanoski. A. J., Van Korff, M. R., Nestadt, G. R., Chahal, R., Merchant, A., Brown, C. H., Shapiro, S., Kramer, M., & Gruenberg, E. N. (1985). Comparison of the lay Diagnostic Interview Schedule and a standardized psychiatric diagnosis. Archives of General Psychiatry. 42, 667-675. Barlow, D. H. (1986). A psychological model of panic. In B. F. Shaw, F. Cashman. Z. V. Segal, & T. M. Vallis (Eds.), Anxiefy disorders: Theory, diagnosis, and treatment. (pp. 93- 114). New York: Plenum. Barlow, D. H.. Vermilyea, J., Blanchard, E. B., Vermilyea, B. B.. DiNardo, P. A., & Cemy. J. A. (1985). The phenomenon of panic. Journal of Abnormal Psychology, 94, 320-328.

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