Behor. REX. T/KY Vol. 32. No. 8, 867-870. pp. 1994

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QUALITATIVE DIMENSIONS OF NORMAL WORRY AND NORMAL OBSESSIONS: A COMPARATIVE STUDY

ADRIAN WELLS’* and ANTHONY P. MORRISON’

‘University of Oxford, Department of Psychiatry, Warneford Hospital, Oxford OX3 7JX, England ‘University of Manchester, Manchester, England

(Receiwd 19 Ocroher 1993)

Summary-Despite the crucial role typically given to negative !houghts in cognitive conceptualisations of emotional problems, few studies have compared the characteristics of varieties of such thoughts. The present study compared the process features of naturally occurring worries and obsessions in a non-patient group. Analyses of variance revealed several significant differences between these types of thought. The relationship between worries and obsessions, and the clinical and conceptual importance of the observed differences is briefly discussed.

INTRODUCTION

Unwanted intrusive thoughts are found in a wide range of emotional disorders. These thoughts occur in both normal and patient populations (Rachman & De Silva, 1978; Salkovskis & Harrison, 1984). Recently, Borkovec and Inz (1990) proposed a clinically important distinction between varieties of thought-verbal thoughts and images-in patients with Generalized Anxiety Disorder (GAD). They suggested the predominantly verbal activity of worry represents motivated avoidance of images. The latter are closely associated with unwanted physiological arousal. Thus, the distinction between thoughts and images is potentially important in understanding emotional disorders. Few studies have compared the characteristics of different types of thought. An analysis of this type is clouded by the interchangeable use of terminology such as worry and intrusive

thoughts in the literature. Moreover, a variety of different thoughts can be classed as “intrusive”, and it is likely that there are a number of sub-types of intrusive thought. Given the findings of Borkovec and Inz (1990), one of the important dimensions on which normal worry and obsessions may differ concerns the degree of verbal vs imaginal thought content.

Turner, Beidel and Stanley (1992) reviewed the literature on worry and obsessions and concluded that there were several differences: (1) worry themes are typically related to normal daily experience whereas obsessions include themes of dirt, contamination etc; (2) the majority of GAD patients are able to identify either internal or external triggers for worry, whereas the majority of obsessional patients seem unable to identify triggers; (3) worry usually occurs as verbal thought whereas obsessions can occur as thoughts, images, or impulses; (4) worry does not appear to be resisted as strongly as obsessions and it is perceived as less intrusive; (5) the content of clinical worries, unlike clinical obsessions, is not perceived as unacceptable.

The aims of the present study were to investigate in more detail the similarities and differences between normal varieties of worry and obsessions. First, we tested whether Ss could make a valid subjective distinction between varieties of their cwn thought given a basic definition. Second, we assessed and compared the process characteristics of these thoughts, such as controllability, dismissability, involuntariness etc., since these dimensions are important in current conceptualis- ations of the phenomena. We also assessed the reliability of these ratings by asking Ss to rate two examples of each thought. In addition, following Borkovec and Inz (1990), it was hypothesized that obsessions would consist of a higher imagery content than worry, and that if worry is used as motivated avoidance of other intrusive thoughts, then worry should be reported as more distracting and less involuntary than obsessions.

*Author for correspondence.

867

868 ADRIAN WELLS and ANTHONY P.MORRISON

METHOD

Subjects

Ss were drawn from undergraduate and post-graduate students and nurses. Ss were asked to volunteer for a study examining whether people could distinguish between two types of naturally occurring thoughts. From an initial sample of 38 Ss, 30 Ss (10 male) returned data for analysis, the mean age of these Ss was 32.79 years (SD = 8.19).

Procedure

All Ss were presented with a diary for recording the content of the first two worries and two obsessions which occurred during a two week period. This was followed by a space in the diary for recording identifiable triggers for the thoughts, and the duration of thoughts. Worries and obsessions were defined at the beginning of the diary. Following Borkovec, Robinson, Prizinsky and Depree (1983) and Borkovec, Shadick and Hopkins (199 1) a worry was defined as: “A related chain of thoughts with a negative theme. Typical examples of worry include thinking about failures in the past or in the future, such as an impending job interview, or thinking about problems in a relationship”. Consistent with Rachman (1981) we defined obsessional thoughts as “A spon- taneous, quick and sometimes recurrent thought that is unacceptable and/or unwanted. Typical examples of intrusive thoughts include thoughts of contamination or of hurting someone that you would not actually wish to”. We omitted from these definitions reference to worries or obsessional thoughts having primarily verbal or imagery content since we intended to independently assess the extent of verbal or imagery involvement in these types of thought. (Note: we used the term “intrusive thoughts” instead of obsessions on the diary since the term obsession in everyday usage has connotations which are very different from the clinical usage of the term).

The diary contained several rating scales (&loo) anchored at either end by “not at all” and “extremely so, could not be more so” for each type of thought recorded. The following dimensions were rated for each reported thought: intrusiveness; how realistic the thought was; involuntariness; controllability; dismissability; how distracting the thought was; how attention grabbing; distress; compulsion to act; resistance. There was also a scale for rating the percentage of verbal vs imagery content for each thought, the scale ranged from “all images” to “all verbal”. The first page of the diary explained that worries and “intrusive thoughts” were normal phenomena experienced by most people, and that over the next two weeks (although it may require less time) Ss should try and record two worries and two “intrusive thoughts” and rate the dimensions in the diary. This should be done as soon as possible after experiencing the thoughts. All responses were anonymous.

In order to assess the reliability of Ss distinction between worry and obsessions, each description of thought content was written out excluding leading words like “worried, worrying, intrusive” and the list presented to an experienced clinical psycho16)gist for independent classification of thoughts as worries or obsessions, the duration of each thought was also given.

RESULTS

The inter-rater agreement (Kappa) between the clinical psychologist categorization of thoughts (based on content and duration) and the Ss categorization was 0.63. The moderate size of this coefficient confirms that normal Ss were able to make a reasonably valid discrimination between types of their own thought when provided with the present definitions.

All Ss reported having experienced worries over the two week period, although one S reported only one episode of worry. Two Ss reported having no obsessional thoughts over the same period. Thus, 93% of our sample gave data on the two types of thought. Univariate repeated measures analyses of variance with two within Ss factors (first vs second thought; worry vs obsession) and Bonferroni Correction for multiple comparisons were used to analyze the duration and all rated dimensions of the thoughts reported. The results of these analyses and descriptive statistics for the dimensions measured are displayed in Table 1.

There were no significant differences in the dimensions measured for the first vs second example of each particular type of thought. This suggests that the dimensions measured are relatively stable within Ss for a single thought type. Comparison of types of thought revealed a number of

Worry and obsessions 869

significant differences. Worry was reported as consisting of significantly greater verbal content than obsessional thoughts. The latter consisted of more imagery. Compared to obsessions, worry was significantly more realistic, more voluntary, and associated with a greater compulsion to act, compared with obsessions. Worry also was reported to last significantly longer than obsessions, Finally, it should be noted that worry was also rated as more distracting and less dismissable than obsessions but these differences became non-significant following Bonferroni’s Correction. No significant differences were observed for intrusiveness, controllability, distress, resistance or how attention grabbing each type of thought was.

DISCUSSION

For the purpose of this study it was necessary to present Ss with basic definitions of worry and obsessions. It is likely that this produced demand which influenced Ss’ ratings of particular thought dimensions. However, by comparing the two different types of thoughts on the dimensions which were implied by the definitions we can validate Ss’ ability to distinguish between worry and obsessions. Obsessions were rated as significantly shorter in duration and more involuntary than worries, consistent with the definition of obsessions as “spontaneous, quick and unwanted”. This result, combined with the Kappa result, suggests that Ss were making valid reports of worries and obsessions. The following important dimensions are not likely to have been influenced by demand present in the definitions: proportion of imagery/verbal content; intrusiveness; realism; dismissabil- ity; distracting, attention-grabbing; compulsion to act; and resistance.

The results demonstrate that there are clear qualitative differences between normal worries and normal obsessions supporting the view that these events are differentiable (Brown, Moras, Zinbarg & Barlow, 1993). Consistent with our predictions based on Borkovec’s theorizing (e.g. Barkovec et al., 1991) worry was rated as involving predominantly verbal rather than imagery material. The converse was true of obsessional thoughts. The present data also provide preliminary support for the hypothesis that worry is more distracting and less involuntary than obsessional thoughts. This is consistent with the view that worry is a more strategically driven conceptual activity than obsessions (Wells, 1994; Wells & Matthews, in press).

In contrast to the conclusions of Turner et al. (1992), we found that worry and obsessional thoughts did not differ significantly in terms of the extent they were resisted or the degree of intrusiveness. In addition, there were no significant differences in the perceived controllability of normal worry and obsessions. However, these similarities and differences may show a different pattern in clinical states of worry and obsessionality.

An unexpected finding of this study was that Ss reported a significantly greater compulsion to act on worries than on obsessional thoughts. This is also consistent with the observation of Craske, Rapee, Jackel and Barlow (1989) that the majority of patients with Generalized Anxiety Disorder and normals report some “corrective, preventative or ritualistic” act in response to their worry. This is of particular interest because compulsive behaviour (overt and covert) is considered to be

Table I. Thought measures for the first and second recorded examples of each type of thought

Variable

WClrries Obsessions Main effects for:

First Second First Second TYPO Example M SD M SD M SD M SD F(l.26) F(l.26)

Duration Imagery/verbal % Intrusive Reahstic Involuntary Controllable Dismissable Distracting Attention grabbing Dtstressing Compelled to act Resistance

1.6 7.1 10.4 13.8 2.4 5.9 I.6 2.9 26.07* 0.06 68.5 22.8 58.2 22.8 29.6 30.9 29.8 31.0 41.76* I .36 61.3 21.5 60.6 28.5 72.6 23. I 64.4 28.4 I .72 I .38 66.9 26. I 68.9 24.7 41.9 33.3 37.6 31.4 31.15* 0.06 54.4 28.7 59. I 29.2 79.4 20.3 80.6 16.3 19.14’ 0.58 50.2 22.4 49.2 20.3 54.2 29. I 55.0 28.3 0.89 0.01 41.9 21.9 41.5 25.9 58.0 30.4 56.9 29.4 9.16 0.04 62.4 21.9 62.8 18.9 55.7 26.7 52.8 27.9 7.12 0.10 73.9 16.6 66.7 19.4 73.3 15.1 63.5 26.5 0.23 7.04 62.4 24.0 63.0 23.9 61.3 30.9 59.1 34.2 0.29 0.04 45.0 29. I 40.6 33.7 19.1 25.5 25.2 33.3 15.29* 0.02 34.8 23.0 41.1 29.8 47.6 29.8 43.0 34.3 2.51 0.04

,Vo/e: N = 27. Significance level l (f < 0.05) after Bonferroni’s Correction No type X Example interaction reached significance (P > 0.05). Imagery/verbal %: higher number = more verbal.

870 AURIAN WELLS and ANTHONY P. MORKISON

important in the maintenance of obsessional problems (Rachman & Hodgson, 1980) but it has not been explicitly linked to worry. The appraisal of obsessions is considered to be a determinant of compulsive behaviour (McFall & Wollensheim, 1979; Salkovskis, 1985). Wells and Matthews (in press) suggested that the key aspect of appraisal involved in the maintenance of obsessions is whether the appraisal is perservative verbal rumination (worry) rather than fleeting negative automatic thoughts. Worry could underlie compulsive activity associated with obsessions, and worrying may be involved in the transformation of normal obsessions into obsessional problems. Worrying about obsessions and also worry about worry, which has been labelled meta-worry (Wells, in press) may be a pathologising factor. In general, worry may lead to a generalization of retrieval cues in memory for intrusive thoughts. This may lead to a pre-occupation with intrusions, and may divert attention away from emotional processing of other types of thought, namely images, and thereby contribute to an incubation of intrusions (Wells, 1994).

The present findings suggest that worrying may be voluntary. This is consistent with the view that worry may be used by Ss as a processing strategy for dealing with threat and/or it has other appraised advantages which motivate its usage. However, it is perceived as being uncontrollable to a similar degree as obsessions. In future studies which address the controllability issue it will be important to differentiate between the initiation of worry and its continued execution. The control ratings for these separate dimensions may dissociate in specific worry episodes. Heightened uncontrollability appraisals seem to differentiate abnormal from normal types of worry (Craske et al., 1989). It is possible that abnormal worriers differ from normal worriers in their general efficacy of thought control, in the types of worry control strategy used, some of which may be counterproductive, or they may merely believe worry is uncontrollable when this is not the case. Combinations of these factors and general beliefs about worry could be responsible for the use of worry as a processing strategy and for heightening perceptions of uncontrollability of the activity.

A~X-noM,k~~~~emenrs~Adrian Wells is grateful to the Medical Research Council U.K. and the Wellcome Trust for their support,

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