Cognitive processes in anxiety

Adv. &ho. Res. Thu. Vol. 5, pp. 51-62, 1983. 0146-6402/83 $0.00+.50 Printed in Great Britain. All rights reserved. Copyright @ 1983 Pergamon Press Ltd

COGNITIVE PROCESSES IN ANXIETY

Gillian Butler* and Andrew Mathews? *University Department of Psychiatry, Warneford Hospital, Oxford OX3 7JX, U.K.

tDepartment of Psychology, St. George’s Hospital Medical School, Cranmer Terrace, Tooting, London SW17 ORE, U.K.

Abstract - Clinical reports suggest that anxiety states are associated with cognitions concerning danger. Since judgements of the risk of an event are thought to be influenced by judgemental heuristics such as availability of cognitive representations of such events, it was hypothesised that anxious individuals should overestimate subjective personal risk. This was confirmed in a comparison with matched control subjects, although patients who were also depressed as well as anxious over-estimated risks to at least the same extent. Results were interpreted as supporting an interaction between anxiety and the availability of ‘danger schemata’.

INTRODUCTION

Cognitive processes in depressed patients have been analysed in some detail over the past decade (e.g. Beck et al., ‘1979; Teasdale, 1982). As a result, we now can begin to see some relationships between cognitive processes and the symptoms of depression, and to develop clinical treatments that ameliorate depression. There is no equivalent theory, or at least no very detailed one, in the field of generalised anxiety, despite a longer history of psychological investigation, and the widespread use of cognitive methods in the treatment of anxiety (Mathews, 1983). The few relevant clinical reports in the literature suggest that anxiety states are associated with cognitions that differ in some important characteristics from those associated with depression. Beck et al (1974) collected data from thirty-two patients with anxiety neurosis. On the basis of interview data, he concluded that all patients could identify cognitions related to danger that were associated with periods of anxiety, and twenty- eight out of the thirty-two patients who had acute anxiety attacks “observed that they consistently had thoughts or visual fantasies, or both, revolving around the theme of danger just prior to or during the onset or exacerbation of anxiety”. The most common themes cited were those of disease, death, social rejection or failure. Similar themes were reported by Mathews and Shaw (1977) in a smaller sample of patients with anxiety neurosis.

Despite the lack of appropriate controls in these reports, other studies also suggest a link between cognitive processes concerned with danger and anxiety states. Gentil and Lader (1978) contrasted the written accounts of dreams obtained from anxious patients with those from normal controls. Using an

*To whom reprint requests should be addressed.

51

52 G. Butler and A. Mathews

objective method of content analysis, they found that the dreams of anxious patients showed a significant excess of material concerning failure and aggression directed against the dreamer.

Finlay-Jones and Brown (1981) separated severe life events, or threats, which they classed as “dangers” from those termed ‘losses’, and found the former to be more associated with the onset of anxiety. Since “danger” here refers to anticipated future events, presumably it is the cognitive assessment of these events that determines the mood experienced. When the event is in the future (i.e. it is still a danger and not, as yet, a loss), anxiety appears to be a more common reaction than depression. The idea that the expectation of danger induces anxiety has obvious face validity, and when judged appropriate may be considered normal. However, the degree to which individuals react in the same circumstances will vary, presumably because some individuals are less biologically vulnerable, or interpret the event differently, or have more effective coping resources.

Before considering what may determine individual susceptibility to psychological threat, we need to consider how the risk of dangerous events is usually estimated by non-anxious people, and what determines the level of that estimate. When inaccurate estimates of risk are made, they can arise from at least two sources; the use of judgmental heuristics such as availability and representativeness, which reduce complex inferential tasks to simple judgmental operations, (Tversky and Kahneman, 1974), and from the individuals existing “knowledge structures”, beliefs, theories or schemata (Nisbett and Ross, 1980).

An individual is considered to be using an availability heuristic whenever “stimuli are judged as frequent, probable or causally efficacious to the extent that they are readily ‘available’ in memory” (Nisbett and Ross, 1980, p. 7). Although use of the availability heuristic commonly leads to quite accurate probability estimates, it may be misleading when items are particularly available in memory because of recency, salience or selective exposure effects. For example, Lichtenstein et uZ. (1978) found that causes of death recently publicised by the media in dramatic form (e.g. botulism) may be grossly over-estimated in frequency compared with less salient but more frequent lethal events. Distorted estimates of risk can also result from internally generated representations. Hence, if subjects are required to imagine vividly a possible outcome, then estimates of the likelihood of that outcome are increased (Carroll, 1978). Thus, the detailed nature or vividness of an imaginal event may enhance its salience or accessibility in memory and, hence, increase the estimate of subjective risk.

Use of the representativeness heuristic can lead to a slightly different kind of error in which the individual uses the degree to which a specific event is typical of a general class of events to judge the likelihood that the example is a member of that class. For example, the anxious patient who has a pain in one

Cognitive Processes in Anxiety 53

arm after carrying a shopping basket, and thinks that she is about to have a heart attack, may be making this sort of error. Because the pain is typical of heart disease symptoms, it is mistakenly assumed to be evidence of heart disease, despite the contrary evidence provided by the extremely frequent occasions when a pain in one arm does not indicate heart disease (base rates).

We may not yet be in a very good position to explore the specific beliefs, theories and schemata concerning threat that characterize anxiety. Work on such topics is only just begining in depression as experimental paradigms are developed that can be used to explore hypothetical schemata (cf. Teasdale, 1982; Bradley and Mathews, 1983). Thus, for present purposes we have chosen to avoid offering specific hypotheses as to the exact nature of possible anxiety- generating schemata, other than to assume that they could be associated with a high rate of verbal cognitions or imagery related to danger, as described by Beck et uZ. (1974) and Mathews and Shaw (1977). The characteristics one might expect to find associated with persistent anxiety include an increased availability of threat-related data in memory, a raised sensitivity to anxiety related cues in the environment, and an increased tendency to label or categorise input as threatening (derived from use of the representativeness heuristic), all of which would lead to an over-estimation of subjective personal risk.

At this stage, no predictions are made about the direction of causality among the several variables explored (i.e. mood, cognitions concerning danger, and estimates of personal risk), Rather, the usefulness of the general framework proposed here is assessed by testing some general propositions that should hold regardless of the direction of causality. These are that: (1) people suffering from generalised anxiety will be more likely than others to interpret ambiguous material as threatening, (2) aversive events will be rated as more threatening (or more subjectively costly) by anxious than non- anxious people, and (3) the subjective probability of such threatening events will be higher for anxious than for non-anxious people.

METHOD

To test these general propositions, three questionnaires were developed and administered to a sample of patients with anxiety neurosis, and to matched normal controls. To determine whether or not any differences found were specific to anxiety or were more generally associated with mood disorder, a further matched sample of depressed patients was also included.

Subjects

A total of thirty-six subjects were included in the study; twelve anxious patients, twelve depressed patients and twelve controls. Patientsconformed to


the research diagnostic criteria for either generalised anxiety disorder, or major depressive disorder (Spitzer et al., 1978), and most were currently attending a day hospital or an out-patient clinic. The groups were matched for sex (eight women and four men in each) and as closely as possible for age and educational level.

Procedure

Suitable patients were approached and asked to participate on a voluntary basis, after explaining that the study involved filling in three questionnaires and two rating scales, taking about half an hour. General anxiety and depression were assessed using the Leeds scales (Snaith et al. 197(j), and anxiety at the time of rating was rated using a visual analogue scale.

Questionnaires

Questionnaires were designed to elicit data relevant to each of the three propositions given above. Some general considerations concerning the nature of threatening events are first discussed, since they influenced the development and content of all three questionnaires.

Threat has sometimes been defined as the product of cost and probability (e.g. Carr, 1974). Thus, an event might be considered threatening due to either high cost or high probability or both. For this reason, a sub-set of items rated on both subjective cost and subjective probability was included (see below). In choosing threatening events, account was taken of the common themes reported by Beck ef aZ. (1974) and Gentil and Lader (1978). Questionnaire items were collected that focused on threats of these types, while avoiding items that could be construed as losses (Finlay-Jones and Brown, 1981). Since the implicit demand to give accurate estimates might obscure cognitive biases due to the availability of veridical information, items were deliberately hypothetical in nature. Similarly, subjects were required to respond in terms of their tirst thoughts or impressions.

Interpretations

This questionnaire consisted of ten brief, ambiguous scenarios presented in booklet form (e.g. “you wake with a start in the middle of the night, thinking you heard a noise, but all is quiet”). Subjects were first instructed to respond to an open-ended question (e.g. “what do you think woke you up”?). After noting the first response thought of, subjects were instructed to turn the page and arrange three explanations in the order in which they would be most likely to come to mind in a similar situation. In each case, only one of the


alternatives (presented in a randomised position) was judged to be threatening (e.g. “it could be a burglar”). Scores of 3, 2 or I were given according to whether the threatening explanation was placed first, second or third in rank order.

Subjective cost

After first completing five practice questions, subjects were asked to rate twenty threatening items on a O-8 scale in answer to the question “how bad would it be for you . ..?” Eight of these items were matched with almost identical items on the subjective probability questionnaire so as to allow calculation of composite threat scores (i.e. cost x probability).

Subjective probability

This consisted of thirty-six items, each of which was rated on a O-8 scale of subjective probability from “not at all likely” to “extremely likely”. Both positive (or pleasant) and negative (or unpleasant) events were included, to control for general differences in the use of the rating scale. Similarly, self- other differences were examined by the use of 12 matched pairs of items, (6 positive and 6 negative) so that within each pair one version was referred to oneself, and the second to another person. The other person concerned was either left unspecified or was a specific identifiable individual with no obvious connection with the rater. The two items within any one matched pair were separated, and then randomly distributed within the questionnaire, to reduce the possibility that respondents would identify related items and match their responses to them. Some care was taken to ensure that items were relevant to everyone, by the use of hypothetical items (for example “if you had to ask a bus conductor to change a D note he would be rude to you” or “if you surprised a burglar in your own home he would attack you”). Care was also taken that none of the items could be confounded by performance factors associated with anxiety (e.g. “you will make a fool of yourself’ would not be acceptable).

RESULTS

Characteristics of the samples tested are shown in Table 1. There were no significant age differences between the groups. On both measures of anxiety, the anxious groups differed reliably from the control group, Anxious patients also differed from the controls on the Leeds scale depression scores (7.1 compared to 1.8), suggesting that they were also slightly depressed, although less so than the depressed patients. The recommended cut off point distinguishing depressed patients from normal controls is between 6 and 7.


As expected, the depressed patients obtained higher scores than did anxiety patients on the depression scale, but on the other hand their anxiety scores were at least as high as the anxious group. Thus, the group of depressed patients must be regarded as both anxious and depressed, although the groups are more similar with respect to anxiety than depression.

Scores from each of the three questionnaires were analysed using one-way analysis of variance and ‘r’ tests except in the case of subjective probability, where additional three- and two-way analyses of variance and Tukey tests between means were required.

Table 1. Sample Characteristics

Mean Age (N=l2) Women (8) Men (4)

Anxiety 0- 100

Anxiety (Leeds Scale)

Depression (Leeds Scale)

Normal Anxious Controls patients

30.0 29.3 24.6 24.6 40.8 38.8

9.6= 47.-/b

2.9= lO&

1.h 1. lb

Depressed patients

36.1 32.3 43.8

56&*

ll&

12.5c

*Means sharing a subscript do not differ significantly; p<.Ol for all differing subscripts.

Interpretations

Group differences support the prediction that anxious people are more likely than controls to interpret ambiguous situations as threatening. However, the depressed subjects obtained scores very similar to those in the anxious group, and were also higher than controls (see Table 2 for means and significant differences). The difference between both patient groups and the controls was significant.

Although more subject to subjective bias, open-ended responses were scored by deciding whether or not they could be classified as a threat. Out of a possible total of ten, a mean of 2.3 were judged to describe a threat in the case of the control group, compared with 4.0 for anxious and 3.9 for the depressed subjects. There were no significant differences among these means however.

Subjective cost

The mean subjective cost scores (summed across all items) were higher for both patient groups than for the controls, although unexpectedly the scores of


the depressed patients were reliably higher than those of the anxious patients (see Table 2). Analysis of the sub-set of items rated for both cost and probability is also shown in Table 2. There was no difference between the anxious patients and the controls on the mean subjective cost scores for the sub-set, possibly because the eight items matched with probability questions contained a relatively high proportion of severe items (e.g. getting stomach cancer or heart disease), all of which were rated by everyone as costly. The difference between the depressed patients and the controls on this sub-set was slightly larger, however, and did reach significance. A measure of overall threat (calculated by multiplying the cost and probability scores for the same item) clearly distinguished both patient groups from the controls (see Table 2).

Table 2. Group Means for Interpretations, Cost and Cost x Probability Scores

Normal controls

Anxious patients

Depressed patients

Interpretations: Total Spontaneous negatives

Subjective cost: Total

Cost and probability Cost (8 items) Probability (8 items) Cost x probability

16.ga 2.3

64.ga

4O.L 18.0= 85.3a

2l.h 4.0

ll.c&

44&ib 29.4

166.k

21.&* 3.9

89.0c

‘%8.& 31.8b

202.k

*Means sharing a subscript do not differsignificantty;p<.Oi for all differing subscripts except total cost, anxious vs controls and anxious vs depressed both, p<.O5; and probability 8 items, anxious vs controls, p<.OS.

Subjective ProbabiIity

Separate analyses of variance were carried out for mean subjective probability scores produced by summing ratings for all positive or all negative items. These showed no significant group differences for positive items. However, there was a difference between the control group and both patient groups for the negative items (see Table 3). The sub-set of matched items, relating either to the self or to some other person, was analysed next. A three- way analysis of variance was used to examine for effects due to groups, valence (positive vs negative items), and reference (self vs other). There was a main effect of valence (F,,jj = 10.88,~K.O05) a groups times valence interaction (I& = 8.94, p<.OOl), and a valence times reference interaction (F,,jj = 12.33, ~1<.005). The main effect of valence together with the interactions with groups


Table 3. Group Means for Subjective Probability Scores Divided by Valance (Positive-Negative) and Person (Self-Other)

Normal controls

Anxious patients

Depressed patients

Mean score per item Positive 4.0 4.3 3.9 Negative 2.k 3.2b 3.9t,*

Matched Pairs: 6 items each: Positive self 22.3 23.8 19.3

other 21.9 24.3 22.5 Negative self 13.L zi?.&, 25&

other 12.8a 16.b 21.3b

*Means sharing subscripts do not differ significantly. See text for significance level of scores with different subscripts.

and with reference, indicate that group differences in the response to items referred to the self or to some other person differ according to the valence (positive or negative) of the items. In order to locate the source of this difference, two-way analyses of variance (groups x reference) were run on data concerning subsets of positive and negative items separately. The mean scores from these analayses are also shown in Table 3. The groups did not differ significantly in their responses to the positive items, but they do in their responses to the negative items. In the analysis of negative items, there was a main effect of groups (Fz,r3 = 6.65, ~<.005), and of reference (F,,jj = 23.79, p<.OOOl), and a groups times reference interaction (& = 4.85, ~<.05). Anxious patients have a higher subjective probability for negative threatening events, if those events are predicted for themselves rather than for some other person (Tukey test, p<.Ol). They also think that the same events are more likely to occur to themselves than do non-anxious controls (Tukey test, ~~<.05), while the rated probabilities for others do not differ significantly between these two groups. Depressed patients, on the other hand, rate both self- and other-related negative events as more probable than do controls (Tukey tests, p<.O5 in both cases). They also show a self-other difference (Tukey test, p<.O5). These findings are illustrated in Fig. I.

AnaIysis of Individual Items

One way analyses of variance were performed on each questionnaire item to determine which items were contributing to the differences found between groups in total scores. Patients differed from controls on only two positive items in the probability questionnaire, but eight negative items, six of which concerned the self. Thus, both anxious and depressed patients judged the


6 POSITIVE ITEMS

-- - - - - .e-.-- ANXIOUS

I I SELF OTHER

6 NEGATIVE ITEhlS

- - - - - - - - CONTROL

, I SELF OTHER

FIG 1. Subjective probability: matched pairs

probability of a fire in their home, being attacked by a burglar, a heart condition, cancer, a disagreement with a friend, or an unspecified dreadful event, as more likely to happen to them than did normal controls. Similarly, patients judged the subjective cost of being stuck for conversation, being criticised, knocking over a drink, being the object of rudeness, having someone unexpectedly late in returning, home, or having a minor operation, as greater than did controls. Only one ambiguous situation - a pain in the chest without obvious cause - was judged significantly more threatening on the interpretations test.

In almost all of these differences there was a non-significant trend for depressed patients to be more pessimistic in their estimates than the anxious patients. It would seem that a majority of events seen as more probable by both groups of patients than by controls refer to physical dangers, while the events seen as more costly tend to be more frequently social. This may be an artifact of the rating scales used however, since physical dangers tended to show a ceiling effect on cost ratings, and social difficulties show a similar effect on probability ratings.

DISCUSSION

Considering first the differences between the anxious and control groups, there is some support for each of the three hypotheses outlined earlier. Anxious patients were more likely than non-anxious controls to interpret ambiguous material as threatening. They also rated the subjective cost of threatening events as higher than did controls. Both group differences suggest that they give greater cognitive weight to threatening information. However,

60 G, Butler and A. Mathews

depressed patients did not differ from anxious patients in this respect, indicating that the tendency to do this may be common to both types of mood disturbance, at least when depression is accompanied by anxiety.

Results from the subjective probability questionnaire allow for somewhat detailed and hence more informative analysis. In the first place, it seemed that group differences in these inferences were specific to negative events. Anxious (and depressed) people did not seem to think that positive events were more or less likely to happen to themselves than to others, nor were there any differences in this respect from normal controls. However, anxious subjects tended to think that negative threatening events, in particular, relatively severe threats to their health, were more likely to happen to them than to someone else. In this they were different from control subjects, who gave equivalently low probability scores in both conditions. Depressed patients were not significantly different from anxious patients, but showed significant elevations in subjective probability for all negative events, whether concerning themselves or others.

When these results are looked at in combination with the mood ratings, interpretation becomes somewhat more complicated. It is obvious that both patient groups were to some extent both anxious and depressed, although the depressed patients suffered more from anxiety than the anxious patients did from depression. The results could therefore be attributed to the cognitive effects of depression seen in a mild form in the anxious group and in a more severe form in the depressed group. However, an equally if not more likely explanation is that the results are attributable to the high levels of anxiety found in both groups. Although this explanation may appear plausible, other possibilities need to be discussed before considering mechanisms that may link anxiety and subjective probability.

It could well be that any mood disturbance may lead to increases in negative expectations for oneself, and that this effect is not specific to anxiety. Qualifying this alternative explanation however, the non-significant tendency for depressed patients to show less discrepancy between ratings for self and other than did anxious patients, suggests that the two patient groups may indeed think in somewhat different ways. Possibly, depressed patients react in a relatively stereotyped way by assessing all negative events as more likely. This would be consistent with the operation of Beck’s cognitive triad, according to which depressed patients are said to have negative views about themselves, the world and the future. Anxious patients on the other hand, may not regard the world as a universally unpleasant or dangerous place; rather they might see themselves as especially at risk.

This explanation seems consistent with clinical observations (e.g. Beck, 1976, p. 164) that state anxiety and subjective estimation of personal danger are correlated over time. A patient fearful of flying reported marked increases in subjective probability of an aircraft crash as the time approached to make a


flight. When not planning a flight himself, estimated probability of an air crash (involving other people) was put at one in a thousand. This estimate increased sharply and eventually reached 50 : 50 just before the patient was due to take off on a flight himself.

How could such clinical observations be explained? In discussing a series of studies of mood-dependent memory effects, Bower (1981) has proposed that memories of past events may become more accessible if they are congruent with present mood state. In his network model of memory, the cognitive representation of emotional states is linked with that of mood-congruent events that have occurred in the past, so that activation ofeach may prime the other. For instance, the presence of a particular mood will increase the probability of remembering events that previously provoked that mood, and memory of such events will be likely to increase the associated mood. Assuming such a network model, it follows that anxiety may make memories about past dangers more available, while activation of such “danger schemata” will increase the probability that anxiety will be aroused, due to the relatively strong link between the cognitive representations of emotional states and mood congruent events. It thus becomes possible to postulate a circular interactional model of anxiety, similar to that proposed by Teasdale (1982) in relation to depression. The arousal of anxiety following a real or imagined threat will activate memories of other mood-congruent events (“danger schemata”), thus inflating estimates of present risk, and maintaining or even enhancing anxiety levels, This circular model of anxiety neurosis seems intuitively more satisfying than one involving only a one-way transaction between subjective danger and mood state, in which ever direction.

Such an interaction between mood and memory has a number of important implications for clinical research and practice. For example, Laird et aZ. (1982) in discussing their evidence of a relationship between emotional cues and selective recall, speculated that “such a dynamic might contribute heavily to the development of spreading phobias such as agoraphobia”. If a recurrence of fear leads to easy recall of previous dangers and feelings of fear, then the immediate phobic situation would seem all the more dangerous and frightening.

The model also has important implications for treatment such as anxiety management training, when this involves cognitive coping procedures. These are commonly taught to the patient when in a relatively calm state, and thus they may be relatively inaccessible later on during an anxiety attack. Conversely, during the anxiety attack, cognitions concerning danger suddenly become much more available, leading to the vicious circle effect described previously. Clearly, the implication is that, if a therapist wishes cognitive coping instructions to be available and influential during anxiety, then they must be learned in such a way as to link them with the cognitions concerning

62 G, Butler and A. Mathews

danger and anxiety. One solution would thus be to deliberately invoke anxiety during treatment and then teach cognitive coping methods under these conditions.

It is obvious that more direct evidence of causal relationships between anxiety, cognitions concerning danger, and elevated personal risk estimates must be forthcoming before the interactional model proposed here can be regarded as anything more than heuristic. Similarly, a much clearer cognitive distinction is required between anxiety and depression before it can be claimed that the proposed model is specific to anxiety rather than to mood disorders in general. Despite this, the model seems rich in clinical and research implications, many of which are amenable to direct testing.

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Beck, A. T., Rush, A. J., Shaw, B. F. and Emery, G. (1979) Cognitive Therapy of Depression. Guilford Press, New York.

Beck, A. T., Laude, R. and Bohnert, M. (1974) Ideational components of anxiety neurosis. Arch. gen. Psychol. 3, 319-325.

Bradley, B. and Mathews, A. (1983) Negative Self Schemata in clinical depression. Br. J. clin. Psychol. 22, 173-181.

Bower, G. H. (1981) Mood and Memory. Am. Psychologist 36, 129-148. Carr, A. T. (1974) Compulsive neurosis: a review of the literature. Psychol. Bull. 81, 31 l-318. Carroll, J. S. (1978) The effect of imagining an event on expectations for the event. An

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Cognitive processes in anxiety