استفاده از مقایسه کنترل شده در تحقیقات آسیب شناسی روانی بیزاری: مورد بیزاری، اضطراب و مالیخولیا و اضطراب سلامت

The present paper describes the results of a study investigating the relationship between measures of disgust and measures of hypochondriasis and health anxiety. The results indicated that (1) there were highly significant correlations between measures of trait disgust and disgust sensitivity and measures of hypochondriasis and health anxiety, (2) the relationship between disgust sensitivity measures and hypochondriasis and health anxiety were still significant even when levels of trait anxiety were controlled for, but (3) controlled comparisons revealed that the measures of disgust also predicted scores on measures of disgust-irrelevant control psychopathologies (claustrophobia and height phobia)—even after trait anxiety had been partialled out. In addition, the series of multiple regressions carried out clearly indicated that trait anxiety and disgust sensitivity appear to be independent constructs each of which have relationships with anxious psychopathologies over and above the effect of the other. The discussion explores the nature of the possible relationships between disgust, hypochondriasis and health anxiety, and also looks at the implications for disgust psychopathology research of using controlled comparisons which indicate the existence of significant relationships between measures of disgust and anxious psychopathologies that, a priori, would be considered to be disgust irrelevant.

Research on the disgust emotion has tended to indicate that it is in some way involved in a number of anxiety-based psychological psychopathologies (Phillips, Senior, Fahy & David, 1998; Woody & Teachman, 2000). For example, disgust has been identified as a feature in a variety of specific phobias, including animal phobia generally (Davey, 1994a; Matchett & Davey, 1991), spider phobia specifically (Mulkens, de Jong, & Merckelbach, 1996), blood–injection–injury (BII) phobia (Page, 1994; Tolin, Lohr, Sawchuk, & Lee, 1997), obsessive–compulsive disorder (OCD) (Charash & McKay, 2002; Muris et al., 2000), and eating concerns, where disgust is manifested in disgust of food, the body, and body products (Davey, Buckland, Tantow, & Dallos, 1998). Disgust is a basic universal emotion characterised by a distinctive facial expression and distinctive cognitive (fear of contamination from disgust-eliciting stimuli), behavioural (distancing oneself from the offensive object), and physiological (nausea) components (Davey, 1994b; Rozin & Fallon, 1987). While it is viewed primarily as a food-rejection response, it is also associated with fear of contamination, and with the negative affect associated with morally or socially unacceptable behaviours and activities (Marzillier & Davey, 2004a). In each of the psychopathologies in which its involvement has been implicated, disgust is seen as relevant because the psychopathology contains features which involve some of the relevant elements of the disgust emotion, e.g. food rejection (eating disorders), or fear of contamination (obsessive–compulsive washing), and relate quite obviously to some of the putative functions of the disgust response, such as disease-avoidance (Davey, 1994b) or avoidance of body-envelope violations or death (Haidt, McCauley, & Rozin, 1994). These disorders will be termed “disgust-relevant” (DR) anxiety disorders in order to distinguish them from other anxiety disorders where disgust is not thought to be involved. However, although it seems quite clear that disgust is experienced in DR disorders, there is still no clear consensus about its exact role in psychopathology, and, in particular, whether it has a causal role in the acquisition, maintenance, or intensity of anxious psychopathology ( Marzillier & Davey, 2004b). One anxious psychopathology in which the role of disgust has yet to be properly explored is health anxiety or hypochondriasis. Hypochondriasis is defined in DSM-IV as ‘the preoccupation with the fear of having, or the idea that one has, a serious disease based on the person's misinterpretation of bodily symptoms or bodily functions (American Psychiatric Association (DSM-IV), 1994, p.445). The preoccupation with health in hypochondriasis may be concerned with bodily functions (e.g. heartbeat or sweating), with minor physical abnormalities (e.g. coughing), or with vaguely defined and ambiguous physical sensations (e.g., ‘aching veins’) (American Psychiatric Association (DSM-IV), 1994, p.463). Hypochondriasis and health anxiety are associated with an excessive fear of death (Noyes, Stuart, Longley, Langbehn, & Hapel, 2002), and clinically diagnosed hypochondriacal patients report substantially more thanatophobic characteristics than non-anxious control participants, and seek medical care more frequently (Kellner, Abbott, Winslow, & Pathak, 1987). Hypochondriasis is also associated with an increase in worry about disease, together with fears of specific diseases, an inability to distract from feeling somatic symptoms, and an increased awareness of somatic symptoms after receiving disease-relevant information (Kellner et al., 1987). There may be other disorders related to physical health in which disgust may play a role (e.g. somatoform disorders), but for the purposes of this paper, attention will be focussed on relationships specifically between disgust and health anxiety and hypochondriasis. There appear to be some rather obvious prima facie theoretical grounds for assuming that the disgust emotion might be involved in hypochondriasis and health anxiety. For example, inflated levels of disgust sensitivity are likely to alert the individual to possible sources of contamination, disease and infection, and to facilitate the processing of information about contamination, disease and illness. For example, empirical studies that have used an implicit memory task have found that individuals with a BII phobia recall more medically related words following a disgust mood induction than a neutral mood induction (Sawchuk, Lohr, Lee, & David, 1999), suggesting that disgust does facilitate some aspects of the processing of medically related information. At least one study has found some preliminary evidence for a link between disgust and health anxiety. In a nonclinical, analogue population, Thorpe, Patel, and Simonds (2003) found that disgust sensitivity scores (as measured by the disgust sensitivity scale, Haidt et al., 1994) were significantly related to health anxiety scores (as measured by the Whitely Index, Pilowsky, 1967). The study also found significant inter-relations between disgust sensitivity, health anxiety and obsessionality scores. While the study by Thorpe et al. (2003) does appear to implicate disgust in health anxiety and hypochondriasis, Davey (2003) has suggested that correlational studies of disgust and anxious psychopathologies should begin to incorporate a number of control procedures in order to eliminate what might be some theoretically trivial reasons for any observed association between disgust and the psychopathology. In particular, Davey (2003) has suggested that (1) correlational studies of disgust should always take concurrent measures of trait anxiety in order to control for any mediating role of anxiety in the relationship between disgust and the psychopathology, and (2) correlational studies of disgust and psychopathology have rarely, if ever, used balanced designs in which the relationship between disgust and the DR psychopathology is compared with the relationship between disgust and a psychopathology which is not believed on theoretical grounds to involve disgust. The former is necessary to ensure that the association between disgust and the psychopathology is not simply mediated by concurrent levels of anxiety (or a confounding of the measures of disgust with anxiety), and the latter ensures that any theoretical reason for examining the relation between disgust and the DR psychopathology is tested through a differential prediction. The present paper describes a study investigating the relationship between disgust sensitivity and measures of health anxiety. Using two different measures of disgust (the disgust propensity and sensitivity scale (DPSS) and the disgust sensitivity questionnaire (DSQ)) and two different measures of health anxiety (the Survey of Health Concerns and the illness attitudes scale), it was predicted there would be a significant positive relationship between levels of disgust and measures of health anxiety. This prediction was compared with the hypothesis that there would be no significant relationship between levels of disgust and measures of disgust-irrelevant (DI) anxious psychopathologies (in this case, claustrophobia and height phobia). The study also took a measure of trait anxiety to examine whether any relationships between disgust and measures of health anxiety might be mediated by levels of generalised anxiety.

3. Results 3.1. Relationship between measures of disgust and measures of hypochondriasis and health anxiety Table 1 shows the correlations between the three measures of disgust (DPSS, trait; DPSS, sensitivity; DSQ total) and the SHC and IAS (with an adjusted significance criterion of p<.0015p<.0015 for multiple comparisons). These exhibit significant correlations across all disgust measures, the SHC and most sub-scales of the IAS. The only sub-scale of the IAS that fails to show any significant association with measures of disgust is the health habits sub-scale. Measures of trait anxiety also correlated significantly with SHC [r(110)=.52r(110)=.52, p<.001p<.001] and with all sub-scales of the IAS except ‘health habits’ [all r 's>.35, all ps<.001