The nature and assessment of catastrophic thoughts in panic disorder

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Pergamon

Behav, Res. Ther. Vol. 34, No. 4, pp. 363-374, 1996

0005-7967(95)00075-5

Copyright © 1996 Elsevier Science Ltd Printed in Great Britain. All rights reserved 0005-7967/96 $15.00 + 0.00

INVITED ESSAY THE N A T U R E A N D ASSESSMENT OF CATASTROPHIC THOUGHTS IN PANIC DISORDER B R I A N J. COX Department of Psychology, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2 (Received 23 August 1995; in revisedform 18 October 1995)

Summary--This essay describes the current status of our conceptualization and assessmentof catastrophic thoughts in panic disorder, an area that is more heterogeneous than may first appear. It is suggested that a heuristic approach would involve assessing both 'state' catastrophic cognitions (automatic thoughts) and the underlying 'trait' cognitive factors (beliefs). The cognitive symptoms listed in the DSM-IV and the self-report Anxiety Sensitivity Index serve as useful preliminary measures for assessing these respective domains. The trait cognitive domain is seen as multidimensional and congruence is required with internal or external stimuli in producing state catastrophic thoughts and accompanying panic attacks. Pressing challenges and controversies in this field are also highlighted and strategies for potentially resolving these issues are offered. Accordingly, several directions for future investigation are presented throughout the paper. Examples of innovative assessment techniques are briefly described.

INTRODUCTION Panic attacks were 'officially' introduced and described in the psychiatric nomenclature with the appearance of the third edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-III: American Psychiatric Association, APA, 1980). Since that time, fears of dying, going crazy, or losing control (doing something uncontrolled) have always been listed as panic attack symptoms. However, catastrophic cognitions (CC) have never been deemed essential in deciding on a diagnosis of panic disorder. Indeed, physical symptoms still vastly outnumber catastrophic thoughts or fears as criteria for diagnosing panic attacks and panic disorder (DSM-IV: APA, 1994). This is despite the fact that many individuals equate the term 'panic' with some type of perceived catastrophic element. Although CC appear prominently in the phenomenology of panic, research into this topic has not been as systematic as some would prefer, and several shortcomings or gaps in the progression of research have left many unanswered questions and unresolved controversies. This essay will attempt to critically evaluate our current knowledge on the nature and assessment of CC in relation to panic, with the goal of integrating different lines of investigation, making recommendations for assessment, and outlining specific directions for future research endeavors. Previous reviews have focused on cognitive assessment in social phobia (Glass & Arnkoff, 1994; Heimberg, 1994), and depression (Segal & Swallow, 1994), and some of the issues raised in those articles are relevant to panic disorder. As well, additional information on current assessment techniques obtained from personal communication with many leading clinical researchers will be presented to make this review as state-of-the-art as possible. The purpose of this essay is to offer observations and suggestions for future study. For this reason, and that of brevity, this paper should be viewed as a selective rather than comprehensive review of the literature. Although the title of this paper refers to DSMdefined panic disorder, the context is expanded to include panic attacks as well. I begin with a brief overview of the cognitive perspective on panic. Two of the most influential contributions to this area come from Clark's cognitive model of panic and the anxiety sensitivity construct. 363

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In his seminal paper, Clark (1986) proposed a cognitive model of panic in which panic attacks were viewed as arising from the catastrophic misinterpretation of certain somatic or psychological sensations, and the perception of these sensations as more dangerous than they really are. For example, Clark notes that one may misinterpret palpitations as evidence of an impending heart attack. The trigger stimulus could be either internal or external and for some patients the sensations and interpretations could change over time. In contrast to hypochondriasis, the threat in panic disorder was seen as an immediate danger or impending catastrophe. Clark (1988) further postulated that this tendency to misinterpret bodily sensations was an enduring cognitive trait that would be 'amplified' in an anxious state. It was not clear whether this trait must exist before the occurrence of the initial panic attack. Finally, Clark suggested that this cognitive process could occur at a nonconscious level. This posed some difficult challenges in measurement. As Klein (1994), McNally (1994) and others have noted, this potentially nonconscious process limits the falsifiability of the model, especially in relation to nocturnal panic (more will be discussed on this later). The strength of the cognitive model is arguably in its description of a process or the sequence of events in a full-blown panic attack. The model appears weaker in identifying a measurable trait or individual difference variable that predisposes some individuals to make catastrophic misinterpretations. The anxiety sensitivity construct may provide this missing component; certainly the two perspectives share much in common. The anxiety sensitivity (AS) construct and the 16-item Anxiety Sensitivity Index (ASI) were first discussed in peer-reviewed journals in the same year (in fact in the same journal) as Clark's cognitive model of panic. Reiss, Peterson, Gursky and McNally (1986) described AS as "an individual difference variable consisting of beliefs that the experience of anxiety/fear causes illness, embarrassment or additional anxiety" (pp. 1-2) and forms a major part of Reiss and McNally's (1985) expectancy model of fear. Thus, AS represents a fear of anxiety symptoms based on the belief that these symptoms have harmful consequences. AS is seen as a departure from the Goldstein and Chambless (1978) fear of fear concept in that AS can precede or exist independently of panic experiences, although it is likely increased by panic. In contrast, the Goldstein and Chambless model of agoraphobia describes the fear of anxiety as developing through interoceptive conditioning following the onset of panic attacks. Perhaps for this reason and the fact that it parallels DSM revisions in emphasizing panic rather than agoraphobia, the ASI appears to be gaining popularity compared to the fear of fear scales (Agoraphobic Cognitions Questionnaire and Body Sensations Questionnaire) developed by Chambless, Caputo, Bright and Gallagher (1984). Although AS could be related to several forms of clinical anxiety, it has come to be viewed as a cognitive risk factor for panic disorder. There is extensive empirical support for the AS construct and the ASI (for reviews see McNally, 1994; Taylor, 1995), but it has attracted criticism as well. One of the most enduring areas of controversy is whether AS, at least as measured by the ASI, is a unidimensional or multidimensional construct. As Lilienfeld, Turner and Jacob (1993) as well as Taylor (1995) have observed, it is quite likely that AS is unifactorial on a higher-order level and multidimensional on a lower-order level. Lilienfeld et al. outlined a hierarchical factor model where the facets (dimensions) of AS represent a lower-order dimension of AS. In turn, AS is a facet of trait anxiety, and trait anxiety is a facet of negative affectivity (neuroticism). In the model I will outline shortly, AS is seen as multidimensional. However, it is quite possible that the 16-item ASI is not robust enough to capture the various dimensions of AS, and therefore should be expanded to create a potentially more powerful instrument. Arrindell (1993) provided factor analytic support for a multidimensional approach to the study of related measures, and suggested that the ASI does not have enough items to assess the perceived negative social consequences of anxiety. Other researchers such as Lilienfeld (Lilienfeld, S., personal communication, 13 February 1995) maintain that the ASI contains too few items to tap into cognitive domains, and much of its content is composed of neuroticism or negative affectivity. The Clark (1986) and Reiss et al. (1986) papers have fostered an impressive amount of research activity. Despite the similarity between AS and the cognitive model proposed by Clark, however, there has been a surprising lack of integration between these perspectives, particularly in relation

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to CC. This situation mirrors the status of cognitive work in depression, an arguably more advanced area, where there is a theoretical and practical need to assess cognitive products, processes, and structures (Segal & Swallow, 1994). In the next section an attempt is made toward an integration by outlining an approach inspired by the interactional model of personality (Endler & Magnusson, 1976) and by the interactional model of state and trait anxiety (Endler, 1983). The 'person-by-situation' model emphasizes the multidimensionality of trait anxiety, and proposes that a high level of a particular facet of trait anxiety (e.g. social evaluation) results in state anxiety only when the individual is in a congruent situation. For example, this model predicts that an individual who scores high on a facet of trait anxiety relating to social evaluative concerns and low on a facet of trait anxiety relating to physical danger would experience more state anxiety when he or she is about to give a public presentation than when about to parachute out of an airplane. Four facets of trait anxiety were described in Endler's model: social evaluation, physical danger, ambiguous situations, and daily routines. Although this approach has received extensive empirical support, this does not indicate that the list of facets is a complete one. AN I N T E R A C T I O N A L VIEW OF PANIC If Clark's cognitive model of the panic process is retained and expanded using an interactional approach as a guideline, then AS would be incorporated as follows: Multidimensional Trait (as assessed by an expanded ASI)

×

Congruent Trigger

=

Panic Attack (including state CC)

Multidimensional trait

The trait in this model is viewed as a cognitive predisposition and could be assessed by a measure such as the ASI. On this lower-order level however, and to better capture the process, AS may be better conceptualized as a multidimensional trait. Research into the nature of panic attack symptomatology (e.g. Cox, Swinson, Endler & Norton, 1994) suggests there may be subtypes of panic (e.g. cardiorespiratory, dizziness-related) and panic disorder can be viewed as a heterogeneous condition on a lower-order level. It is therefore quite likely that different specific vulnerabilities exist at a lower-order level (i.e. content) and can still represent a more general catastrophic style at a higher order level (i.e. structure). Theoretically, in the process of catastrophic misinterpretation, these specific traits would be activated by congruent situations and characterized by congruent state CC. At a minimum, AS is probably composed of specific traits representing beliefs about psychological symptoms associated with anxiety and beliefs about physical symptoms associated with anxiety. In fact, 'fear of anxiety symptoms' (i.e. AS) may be part of a broader set of beliefs about unusual or strong internal sensations that may or may not be identified as anxiety symptoms. Some may argue that this extension would stray into the area of hypochondriasis, but it will be shown later that the boundary is not so clear-cut. Similarly, a negative social evaluation component of AS is not necessarily the same as blurring the distinction between panic and social phobia, and fear of negative social consequences is not the same as a general fear of negative evaluation/social sensitivity. That is one may be frightened of the social consequences of anxiety, but not necessarily frightened of negative evaluation in general. Also, there may be a dimension related to an intolerance or fear of strong affect in general rather than fear of anxiety symptoms per se which would result in quite different state CC (e.g. thoughts about personal weakness, lack of personal control). The ASI has proven to be a valuable instrument to date. However, an examination of the items reveals that only one, "When I am nervous, I worry that I might be mentally ill" has clear face validity in regards to the proposed AS construct (i.e. fear of anxiety symptoms based on the belief that they have harmful consequences). Many of the items relate to physical or psychological sensations that may or may not be anxiety symptoms and/or do not directly refer to the associated beliefs. In the future it is recommended the ASI be expanded by adding new items rather than being completely revised, because this would allow more dimensions to be assessed without making

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previous research using the ASI obsolete. One of the greatest difficulties is deciding on how many levels or dimensions to consider without becoming too idiographic. It is more likely that meaningful relations between beliefs and bodily sensations will be found when clusters of sensations (e.g. cardiorespiratory distress) rather than individual sensations (e.g. palpitations, dyspnea) are examined (e.g. Rachman, Levitt & Lopatka, 1987).

Congruent trigger Because the cognitive trait of AS is viewed as multidimensional, the situation or trigger must be congruent with the trait in this process. The trigger may be either internal or external, but should be connected in a meaningful way with the trait. Further, there is a differential prediction in that an incongruent situation should not trigger a response. The subjective meaning or perception of a situation for an individual should also be assessed because this meaning will not always be obvious to an outside observer. However, in stringent evaluations of this process the congruent situational triggers should be defined a priori and not identified in retrospect. By congruence, I refer to the requirement that the stimuli be thematically linked to the underlying trait. For example, a skipped heartbeat or a brief episode of tachycardia is congruent with a trait concerning a belief that cardiorespiratory sensations have harmful consequences (death). Conversely, a sudden episode of dizziness would not be seen as a congruent trigger. This approach parallels work in the depression field where an event such as the termination of an intimate relationship would be seen as congruent with a schemata concerning interpersonal dependency, whereas a vocational demotion would not be seen as a congruent trigger. Further, as with research on depression, the trigger must not only be thematically congruent but also should be subjectively meaningful or relevant for the person as well. To use another cardiorespiratory example, one might expect that a brisk walk would be a thematically suitable trigger for a trait consisting of beliefs that cardiorespiratory sensations are dangerous. However, an individual with such a trait may find that brisk walking results in a steady, strong heart rate and that sitting in a particular position in a chair is more likely to cause him or her to notice a skipped heart beat. Thus, if the meaning or relevance of these situations had not been assessed, it would be difficult to see how a sitting position rather than walking quickly would be a suitable trigger for a person with this type of trait. Finally, more research is needed on the nature of the catastrophic process. For example, does the situational trigger lead to some catastrophic spiral of imagined outcomes or does it bring on an image of some previous catastrophic event? Also, the direction of causality requires investigation to determine if state CC can modify the underlying trait (i.e. bi-directional effects).

State CC and panic The state CC are acute and include those symptoms listed as fear of dying, going crazy or losing control in the DSM-IV. However, to be more accurate they should be considered as thoughts rather than fears; many individuals may fear dying but it is the acute thought or belief in imminent death or other catastrophe that is associated with panic attacks. In fact, both the anxiety sensitivity construct and the DSM editions refer to 'fears'. To lessen confusion between trait and state I have tried to replace 'fears' with underlying beliefs and acute catastrophic thoughts or cognitions throughout this essay. The various editions of the DSM have done much to aid research on panic attacks and panic disorder, but can also limit or restrict the scope of the investigations. Although some CC are captured in the DSM, this 'official' list is by no means exhaustive and too often other types of CC (e.g. negative evaluation, complete helplessness) are not assessed and are therefore assumed to be absent.* The DSM also relies on a categorical checklist approach to state CC. It may be more appropriate to employ a Likert-type severity index or strength of belief in each of the CC that are *The DSM-IV requirement that some of the attacks in panic disorder must be unexpected (spontaneous, uncued) similarly does not encourage the investigation of cognitive processes. Also, in the psychobiologicalmodel developed by Barlow (1988) the initial panic attacks are seen as 'false alarms' that may be an indirect response to stress, mediated by neurobiological factors, and only in later stages of learned alarms and anxious apprehension do cognitive processes become more prominent. Barlow, Brown and Craske (1994) state that while CC may be a diagnostic criterion for panic disorder, their "presence is not essential to the definition of a panic attack" (p. 557).

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present (i.e. dimensional assessment). In addition, not all types of CC are experienced by all individuals with panic and again there is likely congruence between the trait, situation, and state CC during a panic. Thus, at the other extreme, a measure that contains numerous CC and relies on a total score approach to classification is also problematic. State CC are not bound to full-blown panic attacks. The 'what if?.' thinking characteristic of anxious expectation in panic disorder is also a form of state CC and should be assessed. Although it may occur in a variety of situations and appear chronic, it is not the same as a trait variable. This is a difficult distinction and some measures may be combining the two, especially after the person has already experienced several panic attacks. Perhaps one approach to clarifying this distinction is to further assess the negative or catastrophic spiral that can be triggered by the 'what if?.' (i.e. the core state CC during a panic attack may be more closely represented by what feared outcomes are generated from this type of 'what if?.' question). Fridhandler (1986) noted that state and trait can be thought of as 'occurrence and disposition'. An individual can be chronically anxious but this would be seen as chronic state anxiety, because temporal duration is not sufficient to distinguish state and trait. According to Fridhandler's conceptualization, a person could also score high on a measure of trait anxiety (disposition) without ever displaying observable state CC until a congruent internal or external trigger arose. There is also the likely possibility that state CC and the multidimensional trait factors change over time. This stresses the need for phenomenological research into the sequence of events in a panic attack, the possible bi-directional effects of state-trait, and the course of the disorder. For example, an individual may initially misinterpret a specific sensation (e.g. skipped heart beat), which results in a full-blown panic attack. Later this person may come to fear the panic experience (anxious expectation) and resort to escape behaviors. Finally, this person may come to fear losing control or embarrassing him/herself if escape was not possible. Therefore, what began as CC related to physical catastrophe can change over time to CC pertaining to social catastrophe. If the trait dimensions are developed through learning experiences, then it is likely they can be modified by environmental factors. An important research endeavor involves studying the effect of corrective information on modifying these underlying traits and possibly preventing future panic attacks. Two implications of this multidimensional, interactional view of panic for cognitive assessment and research are as follows: (1) It is necessary to distinguish between state CC and cognitive traits or structures, and to assess both state and trait features separately in the same individual. Often this does not occur and investigators often assess only one dimension or rely on a measure that combines physical and cognitive events (e.g. the Beck Anxiety Inventory). There is also little consensus on which measures to use and this complicates the ability to generalize findings. It is recommended that the ASI and severity ratings (rather than a categorical presence/absence) of DSM-IV panic symptoms be used to assess trait and state dimensions respectively, with the understanding that both could be expanded and improved in the future to emphasize beliefs and automatic thoughts. In order to minimize the contamination of the measurement of traits by state effects, it is recommended that assessment take place in as neutral a situation as possible. In other words, both state and trait factors should be assessed in a non-threatening environment where the individual is not in an anxious state. (2) The design and assessment strategies in many studies presently rely on a unidimensional view of panic (i.e. panic is thought of as a single, unitary phenomenon and not as a heterogeneous condition with identifiable subtypes). A multidimensional perspective that includes congruence would represent a significant improvement and could increase predictive power. For example, there continues to be a lack of consistent findings in research on memory bias in panic disorder [referred to by Rapee (1994) as "elusive and inconsistent"]. One possibility could be directly related to the reliance on a unidimensional view. Words such as 'coronary' and 'stroke' may have powerful connotations of danger for some panic disorder patients and produce a powerful effect. The same words in another sample of patients who were more concerned with dizziness or depersonalization would presumably have little effect because of the lack of congruence. Similarly, in panic provocation studies it would be helpful to identify the trait subtypes and then to ensure that the stimulus (situation) was congruent with the trait. Preliminary evidence for this congruent interaction was obtained by Leliot and Bass (1990) in a hyperventilation study. Unfortunately,

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some provocation studies do not even include a cognitive trait measure and thus make it impossible to investigate the potential mediation of the trait on subsequent state CC. C H A L L E N G E S AND C O N T R O V E R S I E S This section of the essay describes several challenges to the cognitive assessment and cognitive model of panic, as currently used in clinical research and practice. Some strategies for possibly overcoming these obstacles will be offered, including implications from the model outlined above.

Are CC really 'cognitive'? As Costello (1992) has astutely observed, research into cognitive processes often relies on assessment techniques that likely fail to differentiate CC from physical sensations. For example, does 'feeling faint' (physical sensation) and 'thoughts of fainting' (CC) denote truly different experiences? Probably not. The same is true for 'nausea' (physical symptom) and 'thoughts of throwing up' (CC). An example of a measure that contains these types of ambiguous items is the Agoraphobic Cognitions Questionnaire (Chambless et al., 1984). This is not to say that an individual can't have thoughts of fainting without actually feeling faint, but rather that existing measures often do not make this distinction. One potential method for improving the measurement and assessment of 'pure' CC would be to further examine the extent of the truly catastrophic element of the CC. This method is commonly used in clinical practice where patients are encouraged to explore the extent of their catastrophic thinking by considering follow up questions such as, "and then what might happen?". In describing their cognitive-behavioral treatment package, Rapee and Barlow (1991) noted that anxious individuals not only overestimate the probability of negative events occurring, but also overestimate the aversiveness of the events. Thus, 'thoughts of throwing up' may well be a largely physical sensation that is certainly an unpleasant or negative event. Perhaps a more comprehensive cognitive assessment for some cases would also include, and maybe should concentrate on, the feared catastrophic consequences of this event (e.g. social humiliation and stigma). To extend this specific example, individuals with a bout of influenza or pregnant women may also experience nausea and thoughts of vomiting (negative event), but presumably do not develop a panic or agoraphobic-like disorder; the absence of feared catastrophic consequences may be a key explanatory variable.

The danger of neglecting 'positive' cognitions At the same time as emphasizing the need to pursue the truly catastrophic nature of CCs in order to better separate cognitive from physical domains, there is also a note of caution on focusing only on the negative or catastrophic element. This is particularly relevant for cognitive assessment of outcome processes in the cognitive-behavioral treatment of panic and agoraphobia. Treatment is directed not only at diminishing or eliminating state CC and corresponding traits, but also at increasing positive cognitions (often referred to as reasonable responses or coping thoughts). Thus, assessing the balance or ratio between negative and positive cognitions becomes necessary. This states-of-mind (SOM) model of psychopathology (Schwartz, 1986; Schwartz & Garamoni, 1986) has been successfully applied to outcome research on agoraphobia (Michelson, Schwartz & Marchione, 1991; Schwartz & Michelson, 1987), although it remains unclear what the 'optimal' ratio between negative and positive cognitions should be. The main implication here is that cognitive assessment will be unduly restricted if it is limited to only investigating the negative (catastrophic) side of an individual's internal dialogue. Importantly, the SOM model predicts that the presence of some negative thinking, rather than none, is optimal and reflects realistic thinking; an assessment procedure that concentrates only on measuring the decrease or elimination of negative thinking would be seen as incomplete. Assessment of positive cognitions could involve idiographic techniques such as thought listing, or using a list of positive and panic-specific* coping thoughts (e.g. "I can get through this") or reasonable responses to CC (e.g. "I can feel very dizzy without fainting"). Because what is 'positive' *Assessment of more general negative(avoidance,emotion-oriented)and positive (task-oriented)coping stylescould also prove to be a useful supplement.

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vs 'negative' will not always be apparent to an outside observer, I would again emphasize the need to assess the subjective meaning of the thoughts for each individual.

The problem of nonconscious cognition Some cognitive theorists such as Clark (1988) hold the view that catastrophic cognitive processes can occur outside of an individual's awareness. Critics of the cognitive model use this statement to paint the model with the same brush as psychoanalysis, claiming that it is unscientific because of its apparent failure at falsifiability. In my opinion this claim misses the mark for the following reason. Some cognitive processes can occur at a nonconscious level, but can still be operationalized and subjected to empirical testing. To illustrate, there is much promising research involving work on attentional, interpretive, and explicit and implicit memory biases in anxiety and anxiety disorders (for reviews see Eysenck, 1992; McNally, 1994, 1995), using techniques such as the modified Stroop paradigm.* The research findings are not always replicated and the nature of the potential biases are not clear, perhaps due in part to the neglect of potential congruent interactions based on panic subtypes mentioned earlier. However, implicit memory tasks (e.g. word stem completion) and measures of involuntary explicit memory (McNally, 1994) in particular, will facilitate future research on CC and panic because these techniques presumably tap into processes that are automatic or outside of an individual's awareness (although McNally has commented that Stroop interference actually argues against automaticity in terms of effortless processing). It is foreseeable that these strategies could capture Clark's nonconscious cognitive processes that are used to explain panic attacks where CC are not readily apparent (e.g. nocturnal panic attacks). Yet there is a glaring paucity of research using these strategies, and the accompanying biases they assess, with individuals who report their panic attacks were not accompanied or preceded by CC. This is an obvious direction for future study. For example, if no evidence of these processes can be found during daytime investigations with individuals who report nocturnal panic, then it makes it more difficult to argue that nonconscious processes are responsible for their nocturnal anxiety (unless diurnal/nocturnal differences also become part of the model). Another useful strategy for assessing CC that may not be readily apparent (e.g. when relying on self-report measures of CC endorsement), involves in vivo thought sampling (Kenardy, Evans & Oei, 1988; Kenardy, Oei, Weir & Evans, 1993). Although this type of assessment technique is probably more often used for research purposes, it may serve a useful clinical function as well in certain cases. Are CC panic-specific? In reviewing the literature in this area, the question arises as to whether CC are truly panic-specific, or whether they occur in hypochondriasis, or are part of some general catastrophic trend in thinking style. Clark (1988) noted that the trigger stimuli in panic attacks tend to be autononomic nervous system responses and can be exacerbated by anxiety, whereas this is not the case in hypochondriasis. However, Clark (1988) also maintains that other sensations (e.g. floaters in the visual field) can be trigger stimuli in panic and yet are not part of an anxiety response. Regardless of the type of trigger stimulus (e.g. skipped heartbeat vs a skin rash), it would seem that the cognitive processes in panic and hypochondriasis are very similar: interpreting these stimuli as more dangerous than they really are. Another cognitive difference between panic and hypochondriasis that is often cited is the immediacy of the perceived threat. In the case of panic, the threat is seen as more imminent and in hypochondriasis it is more long-term or delayed (Clark, 1988). McNaUy (1994) states that individuals with a high level of AS may believe that anxiety sensations can 'lead' to catastrophic consequences (p. 116). Presumably, in the case of panic this 'lead' refers to more immediate than delayed consequences. Clinically, however, some patients may come to realize that they will *Cognitive researchers are often quick to criticize many biological findings as mere correlates or consequencesof panic, rather than causes. However,the same criticism can apply to cognitive research that interprets positive findings (e.g. attentional bias) as providing support for a cognitive basis of panic. If a cancer patient demonstrated a bias for the word 'tumour' we would presumably not infer a cognitive etiology for cancer.

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probably not have a heart attack or stroke during an anxiety episode, but may still be convinced that all these episodes of high arousal must be doing some long-term or delayed heart or brain damage. It is not clear if this would represent a different form of AS, or whether it is now hypochondriasis. To some observers, these appear to be rather fine distinctions between panic and hypochondriasis, and in the actual practice of panic assessment these boundaries are often not so clear-cut. For example McNally, Riemann, Louro, Lukach and Kim (1992) conducted an attentional bias study that compared panic disorder patients, obsessive-compulsive disorder patients, and normal control Ss. Five word types were used: neutral, positive, fear, bodily sensations, and catastrophe. One of the interesting findings of this study is that the strongest interference effects were not with fear (e.g. panic attack, terror) or bodily sensations words (e.g. dizzy, breathless). Rather, the greatest interference was for catastrophe words (e.g. dying, brain tumour), which do not appear to be anxiety or panic-specific. Similarly, Asmundson and Stein (1995) recently reported a failure to replicate previous findings (Asmundson, Sandier, Wilson & Walker, 1992) of selective processing in panic disorder patients compared to healthy control Ss. In attempting to interpret this null finding, the authors noted that the words employed in their previous study reflected themes of general catastrophe (e.g. ambulance, cancer); in their subsequent study the catastrophe words were more panic-specific (e.g. palpitations, asphyxiated). Other studies such as that of Rapee (1994) included panic-related (e.g. breathless, dizzy) and non-panic words (e.g. tumour, pain) under the category of physical threat. The results from the Asmundson and Stein (1995), Asmundson et al. (1992), and McNally et al. (1992) studies lend support to the idea that CC may reflect a more generalized catastrophic thinking style or trait than has previously been postulated. This catastrophic style may indeed overlap with hypochondriasis and there is a need to compare potential attentional biases in patients with hypochondriasis vs panic disorder. More likely, both thinking styles are represented by a higher-order factor. It is worth noting that compared to the attention given to the higher-order factor of trait anxiety or neuroticism, there has been virtually no consideration of a general fear of death in relation to the development of panic. As mentioned earlier, other potential underlying correlates of CC that could be investigated include beliefs about strong affect (not necessarily just panic), and issues of personal control (again, not only in relation to panic occurrences). This discussion of higher-order traits also raises the under-researched topic of the etiology of these traits. O R I G I N S OF CC AND ASSOCIATED TRAITS An illuminating retrospective study into the origins of CC comes from the work of Ehlers (1993). Panic disorder patients, infrequent panickers, other anxiety disorder patients, and normal control Ss were administered questionnaires to assess early learning experiences with regards to selfexperiences of panic-like symptoms and sick-role behavior, parental experiences with these variables, and uncontrolled behavior and chronic illnesses in parents. All anxiety groups reported more occurrences of panic-like symptoms (e.g. dizziness, dyspnea) and more corresponding special attention from parents compared to normal controls. This was not true for sick-role behavior in the case of common colds. In addition, anxious individuals compared to controls, more often witnessed uncontrolled parental behavior such as rage during intoxication. Finally, individuals with panic attacks, compared to other anxiety disorder patients and controls, also observed more panic-like symptoms and chronic illnesses in their parents. The results from Ehler's study await replication but do suggest that some crucial traits may develop through learning experiences at an early age. Although genetic influences were not examined in this study, the data support the multidimensional view stated earlier that there is likely more than one trait involved (i.e. issues of control and emotions may be as important as catastrophic beliefs around physical sensations). Several recent review papers have addressed the topic of clinical anxiety--including the nature and assessment of CC and panic--in children and adolescents (Kendall & Chansky, 1991; Moreau & Weissman, 1992; Nelles & Barlow, 1988; Ollendick, Mattis & King, 1994; Silverman, 1991). There continues to be debate around the nature and extent of panic and CC in children, but some general conclusions can be made. Panic is more common in adolescents than in children and the

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nature of CC is likely to change over different developmental stages (e.g. CC become more internal-oriented with age). Children do experience panic-related symptoms (e.g. hyperventilation), but spontaneous panic attacks are less common. CC occur less frequently than physiological symptoms and, are more likely to be thoughts of dying than thoughts of losing control or going crazy. In their comprehensive review, Kendall and Chansky (1991) emphasized the role of coping strategies employed by these children rather than simply the presence of CC, and also the tendency for these individuals to 'fake good' in their presentation. Self-statement endorsement was also recommended by these authors over the use of thought-listing assessment procedures. Perhaps because panic is thought by many to be rare in children, there has not been as much interest in developing new techniques in this area of assessment compared to work with adults. One promising exception is the development of a Childhood Anxiety Sensitivity Index (Silverman, Fleisig, Rabian & Peterson, 1991) which was found to have good reliability and validity. It may be useful for investigators interested more in cognitive risk factors than in anxiety frequency. Of course, as with most areas of psychopathology research, more longitudinal data are needed. These types of trait measures may prove useful, especially in answering the question, "If a person has a tendency to catastrophize, why will they end up with panic disorder rather than some other condition such as depression or obsessive-compulsive disorder?". OTHER SELF-REPORT MEASURES OF COGNITIVE FACTORS Aside from the widely used ASI, Agoraphobic Cognitions Questionnaire, and Body Sensations Questionnaire, there are some lesser known self report measures of panic that may be of use for cognitive assessment. The 50-item Catastrophic Cognitions Questionnaire (CCQ: Khawaja & Oei, 1992) and its 21-item modified form (CCQ-M: Khawaja, Oei & Baglioni, 1994) were developed to assess the danger schema proposed by Beck, Emery and Greenberg (1985). Respondents rate each of the items (e.g. 'having a stroke', 'having an accident') according to how dangerous they perceive it to themselves. Khawaja et al. (1994) reported that the scale assesses three factors of catastrophic content: emotional, physical, and mental. Anxiety disorder patients significantly differed from a community sample on only two of the factors (emotional and mental), and none of the factors could differentiate among the various anxiety disorders (Khawaja et al., 1994). This lack of sensitivity could be due to the reliance on a 'danger index' rather than a misinterpretation format. It is likely that both panic disorder and non-anxious individuals would rate a stroke as a dangerous event, but perhaps only the former group would misinterpret a rapid heart rate as a sign of an imminent stroke. In support of this position, Nesse and Klaas (1994) found no differences between anxiety disorder patients and normal controls on risk estimation of 20 aversive events. The 25-item Panic Attack Cognitions Questionnaire (PACQ: Clum, Broyles, Borden & Watkins, 1990) focuses more on state CC in panic and incorporates items from the Agoraphobic Cognitions Questionnaire, the DSM-III-R and non-DSM items. Items are rated according to the 'degree with which catastrophic cognitions dominated thinking' and a total score is calculated. Individuals with and without panic attacks significantly differed on only 5 of the 25 items when a Bonferroni correction was used (Clum et al., 1990). Two unpublished scales, the Panic Appraisal Inventory (PAl: Telch, 1987) and the revised Panic Attack Questionnaire (PAQ-R: Cox, Norton & Swinson, 1992) also contain information on panic cognition. The PAl has the advantage of not only assessing perceived catastrophic panic consequences (physical, social, and loss of control domains), but also 'positive' panic coping statements. To a lesser extent, the PAQ-R also contains both DSM-III-R and non-DSM state CC as well as positive and negative coping strategies. INNOVATIVE ASSESSMENT TECHNIQUES Several investigators provided information about the assessment procedures used at their centers. The final section of this paper highlights examples of innovative techniques that may be of interest to other researchers. At the initiation of therapy, van den Hout and colleagues (van den Hout, M., personal communication, 15 February 1995) conduct an idiographic cognitive assessment they term Central BRT

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Cognitive Misinterpretations (CCM). The clinician works with the patient to develop one to three idiosyncratic CCM in a standard format where "if X bodily sensation occurs, then X corresponding feared disaster will occur". The clinician helps to ascertain that the CCM are truly central, are frightening to the patient, and are not realistic appraisals. CCM are rated on a 0-100 scale, where 0 -- not credible at all, and 100 = absolutely credible. One score is calculated for the 'here and now' and another score relates to the credibility when in a feared situation. These CCM are used as treatment outcome measures, or more accurately as process measures, because each CCM is scored at the beginning of every therapy session. Data on this technique and its relation to other variables are currently being analyzed. The CCM assessment strategy has the advantage of being idiographic enough to capture subjectively meaningful material, but still can be quantified and subjected to empirical analysis. It appears to combine both state CC and an underlying trait, and probably weighs more heavily toward the former. It wilt be of interest to determine whether scores on this measure change with cognitive therapy, and whether or not changes are produced by treatments that do not directly target CC, such as in vivo exposure and pharmacotherapy. A similar idiographic measure, the Belief Rating Form (BRF), is currently being tested as part of a panic treatment study at another center (Brown, T., personal communication, 25 January 1995). Therapists attempt to assess 'most problematic probability overestimation' (e.g. losing control) and 'most problematic catastrophic thought' (e.g. unable to cope with embarrassment), as two separate components. A 0-100 scale is used for each component to score the likelihood of occurrence and ability to cope, respectively. Each is scored such that 100 -- 'definitely will happen' or 'completely unable to cope'. Clark and colleagues (Clark, D., personal communication, 24 January 1995) have developed an outcome measure called the Bodily Sensations Interpretation Questionnaire (BSIQ), which is a modified version of an earlier measure used by Butler and Mathews (1983). It is a less idiographic measure in terms of content and contains two scales with 7 items each. The panic scale consists of 7 scenarios involving ambiguous bodily sensations. All but one of the scenarios describe physical sensations, with cardiorespiratory being the most common type (e.g. "You notice your heart is beating quickly and pounding"). For each of these scenarios patients are asked to respond to the open-ended question "Why?" As well, patients are asked to rate three possible explanations (catastrophic and non-catastrophic) listed on a separate page in the order in which "they would be most likely to come to your mind". The second scale contains ambiguous control items which are presented in an identical format. Many of the control items appear to represent social evaluation. In a study of the efficacy of cognitive therapy, applied relaxation and imipramine in the treatment of panic disorder, Clark, Slakovskis, Hackman, Middleton, Anastasiades and Gelder (1994) found the BSIQ to be a useful measure. The BSIQ-panic scale, but not the Agoraphobic Cognitions Questionnaire, was significantly correlated with a panic/anxiety composite score at follow-up, and was also correlated with relapse in panic patients who initially benefited from treatment. It would be important to compare the BSIQ, which the authors assert is a measure of schema rather than automatic thoughts (state CC), to another trait measure: the Anxiety Sensitivity Index. In addition, the BSIQ is a unidimensional measure and it remains to be shown whether a multidimensional approach may prove more fruitful. It is also worth noting that although Clark et al. (1994) found cognitive therapy to be superior to applied relaxation and imipramine on the BSIQ, these two non-cognitive treatments were superior to a wait-list control on this cognitive measure. CONCLUDING COMMENTS I have attempted to outline our current knowledge on the nature and assessment of cognitive factors in panic disorder. Some of the major challenges and controversies in the area have been discussed and some possible solutions and directions for future study have been offered. After reviewing the literature and surveying several clinical research centers, it is apparent that there is a lack of consistency in assessment techniques. This makes it difficult to generalize findings. It is recommended that both 'state' and 'trait' cognitive factors be assessed and that a multidimensional

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view of the latter factors may prove heuristic. The ASI and CC listed in the DSM-IV are not the final stage in our research on cognition and panic, but if they are included with other more idiographic or newly developed measures it will facilitate the comparison of findings across centers. In addition, more research into the correlates and origins of the cognitive variables appear warranted. As a final note, it was beyond the scope of this paper to examine the many studies on cognitive factors associated with agoraphobia, but this condition is often part of the presentation of panic disorder and should not be overlooked. Although there seems to be a consensus among many that 'full-blown' agoraphobia is usually preceded by panic attacks, there is evidence that agoraphobiclike phenomena may precede initial panic attacks (e.g. Fava, Grandi & Canestrari, 1988). Considerable interest has been directed to the role of panic expectancy in determining or maintaining phobic avoidance, but it is possible that cognitive variables may predispose some individuals towards this type of expectancy-avoidance cycle and the initial panic attack may act like a priming mechanism. Relevant cognitive or personality themes that could be further explored include safety, control, and escape/avoidance tendencies. It is hoped that future research on cognitive factors in panic disorder will not only investigate why panic attacks can lead to panic disorder in some individuals, but also why panic disorder can so often evolve into panic disorder with agoraphobia. Acknowledgements--I am grateful to the several clinical researchers who kindly responded to my request for unpublished material on the techniques they employ to assess catastrophic cognitions in panic disorder patients. I thank Karina Fuentes for her assistance in reviewing the literature and Drs M. Antony, G. Asmundson and E. Johnson, Associate Editor Dr S. Taylor, and an anonymous reviewer for their helpful comments on an earlier version of this paper. Preparation of this paper was supported by the University of Manitoba Research Grants Program and the Manitoba Health Research Council.

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