Disgust domains in the prediction of contamination fear

Differential habituation of fear and disgust during repeated exposure to threat-relevant stimuli in contamination-based OCD: an analogue study

In the present study, participants (N=20) displaying marked contamination concerns were provided 30 min of repeated in vivo exposure to threat-relevant stimuli (cleaning a 'dirty' bed pan), during which time their fear and disgust levels were repeatedly assessed. Results indicated that repeated exposure led to a significant decline in fear but not disgust. The observed decline in fear remained significant after accounting for changes in disgust and vice versa. Although initial disgust was higher than initial fear ratings, differences between the two slopes were not statistically significant. Baseline trait anxiety and global disgust sensitivity levels prior to exposure did not moderate the level of fear or disgust activation during exposure. However, sensitivity specifically related to core and contamination disgust was marginally associated with fear and disgust parameters during outcome. There was also evidence that less fear decline during repeated exposure was associated with higher disgust ratings after the exposure was completed. Theoretical and clinical implications of the present findings for the treatment of contamination concerns in obsessive-compulsive disorder are discussed.

Information processing in contamination fear: a covariation bias examination of fear and disgust

The current study represents the first examination of covariation biases in contamination fear. Using an undergraduate sample we examined covariation bias for specific emotion outcomes (fear specific and disgust specific) associated with contamination stimuli in high contamination fear (HCF; n=32) and low contamination fear (LCF; n=30) individuals. Following random stimulus-outcome presentation participants provided estimations on the proportion of each presented stimulus-expression pairing. Analyses revealed a specific bias for the over-estimation of fear and disgust contingencies among the HCF group, but not the LCF group. The current study also revealed a specific covariation bias among HCF, not LCF, participants to over-estimate the contingency between contamination stimuli and fear outcomes, not disgust outcomes. Further, results indicate that HCF individuals significantly under-estimate the covariation among contamination stimuli and safety outcomes compared to LCF participants. These findings are discussed in terms of theoretical implications for information processing biases in anxiety disorders.

Trait-disgust vs. fear of contamination and the judgmental bias of contamination concerns

Mechanisms by which trait-disgust, i.e. relatively stable individual differences in disgust proneness, affects anxious psychopathology are not well understood. A possible pathway might be the impact of trait-disgust on cognitive processes, which are involved in the anxiety disorders. The present study extends findings on interpretational and attentional bias by investigating the judgmental bias. Based on theories on disgust, it was assumed that trait-disgust is related to predictions of catching a disease. The present study examined the likelihood of becoming ill, the probability of avoidance behaviour, and the urge to wash in relation to disgust-sensitivity, disgust propensity, fear of contamination, and general anxiety using real-life scenarios. Results suggest that disgust-sensitivity makes a unique contribution to a judgmental bias additionally to fear of contamination and even when controlling general anxiety. Future research concerning the causal direction of this bias is warranted.

An exploration of the relationship between mental pollution and OCD symptoms

Rachman [(1994). Pollution of the mind. Behaviour Research and Therapy, 32, 311-314] theorized that a subtype of compulsive washing exists which has its compulsions triggered by feelings of internal dirtiness, or 'mental pollution'. Since this construct was proposed, few empirical studies have examined it in relation to obsessive-compulsive contamination fear. This study represents a validation of the Mental Pollution Questionnaire (MPQ), which was developed for the measurement of mental pollution. Psychometric data were obtained from two studies using non-clinical samples. The final version of the MPQ consisted of eight items and two subscales related to washing and ideation. Higher mental pollution scores were associated with greater obsessions, contamination, and washing symptoms. In addition, MPQ scores were positively associated with inflated responsibility beliefs and thought-action fusion. Lastly, a third study found that both MPQ subscales predicted OC symptoms after controlling for general distress, trait guilt, and disgust sensitivity. Potential uses of the MPQ as a clinical and research instrument are discussed.

Disgust sensitivity and psychopathological symptoms in non-clinical children

There is clear evidence in the adult literature that disgust sensitivity is implicated in various psychopathological syndromes. The current study examined the link between disgust sensitivity and psychopathological symptoms in youths. In a sample of non-clinical children aged 9-13 years, disgust sensitivity was assessed by two self-report questionnaires (i.e., the Disgust Scale and the Disgust Sensitivity Questionnaire) and a behavioural test. Furthermore, children completed scales for measuring the personality trait of neuroticism and various types of psychopathological symptoms. Results showed that disgust measures had sufficient to good convergent validity. Further, significant positive correlations were found between disgust sensitivity and symptoms of specific phobias (i.e., spider phobia, blood-injection phobia, small-animal phobia), social phobia, agoraphobia, obsessive-compulsive disorder (OCD), and eating problems, and these links were not attenuated when controlling for neuroticism. The possible role of disgust sensitivity in the aetiology of child psychopathology is discussed.

Behavioral avoidance and self-reported fainting symptoms in blood/injury fearful individuals: an experimental test of disgust domain specificity

This study examined the specificity of disgust in predicting avoidance in blood/injury (BI) phobia. Participants high (n=38) and low (n=46) in BI fear completed measures of disgust across multiple domains and severity of BI-related fear. They then completed three randomly presented behavioral avoidance tasks (BATs) that consisted of exposure to a 15'' severed deer leg (BI task), a live spider (spider task), and a 'contaminated' cookie (cookie task). Fainting symptoms associated with each BAT were recorded as well. When controlling for gender and BI fear group membership, mutilation disgust contributed unique variance to avoidance on the BI task and animal disgust contributed unique variance to avoidance on the spider task. None of the disgust domains contributed unique variance to avoidance on the cookie task. For the high BI fear group, self-reported fainting symptoms were more pronounced during the BI and spider BAT than during the cookie BAT. Although mutilation disgust was significantly associated with self-reported fainting symptoms on the BI task among the high BI fear group, this relationship became nonsignificant when controlling for BI-related fear severity. Implications of the domain specificity of disgust and its relevance for understanding fainting responses in BI phobia are discussed.

Disgust sensitivity as a predictor of obsessive-compulsive contamination symptoms and associated cognitions

Disgust sensitivity has been hypothesized to play a key role in the etiology and maintenance of several anxiety disorders. The association between disgust sensitivity, trait anxiety, and washing and contamination-related concerns was tested using two different measures of obsessive-compulsive contamination fears using linear structural modeling. Two different models were tested, one where trait anxiety mediated the relationship between disgust sensitivity and contamination fear, and a second model unmediated by trait anxiety. A total of 740 undergraduates completed self-report measures of disgust sensitivity, trait anxiety, and obsessive-compulsive symptoms for course credit. The results indicated that there was insufficient evidence for the mediating role of trait anxiety, and the more parsimonious structural models specifying direct effects between disgust sensitivity and both washing and contamination concerns fit the data well. The results of this research support the central role of disgust in contamination fear.

Specificity of disgust sensitivity in the prediction of fear and disgust responding to a brief spider exposure

This study examined the specificity of disgust sensitivity in predicting fear and disgust responses to exposure to a spider. Participants high (n=22) and low (n=28) in spider fear completed self-report measures of disgust sensitivity, contamination fear, anxiety, and negative affect. They then participated in a behavioral avoidance task (BAT) in which they were briefly exposed to a realistic-looking, but fake, tarantula. Results revealed that disgust sensitivity was associated with fear and disgust responding to the BAT. The association between disgust sensitivity and disgust responding to the BAT remained significant after controlling for gender, spider fear group membership, contamination fear, anxiety, and negative affect. However, the association between disgust sensitivity and fear responding to the BAT was only marginally significant after controlling for the same variables. Contamination fear was also strongly related to fear and disgust responding to the BAT. However, this relationship was fully mediated by disgust sensitivity. These findings indicate that disgust sensitivity has a unique association with aversive responding to spiders. The implications of these findings for better understanding the complex role of fear and disgust as they related to disgust sensitivity in spider phobia are discussed.

Structural differentiation of disgust from trait anxiety in the prediction of specific anxiety disorder symptoms

Research has begun to implicate the role of disgust in the etiology of specific phobias and obsessive-compulsive disorder (OCD). However, it remains unclear if the association between disgust and specific anxiety disorder symptoms is an artifact of trait anxiety or a potential mechanism through which trait anxiety effects specific anxiety disorder symptoms. The present study employed structural equation modeling to differentiate disgust from trait anxiety in the prediction of four types of specific anxiety disorder symptoms in a non-clinical sample (N=352). Results indicate that disgust and trait anxiety latent factors were independently related to spider fears, blood-injection-injury (BII) fears, general OCD symptoms, and OCD washing concerns. However, when both variables were simultaneously modeled as predictors, latent disgust remained significantly associated with the anxiety disorder symptoms, whereas the association between latent trait anxiety and the anxiety disorder symptoms became non-significant or was substantially reduced. Statistical tests of intervening variable effects converged in support of disgust as a significant intervening variable between trait anxiety and spider fears, BII fears, and OCD symptoms (particularly washing concerns). The relevance of these findings for future research investigating the role of disgust in specific anxiety disorders is discussed.

Examination of the decline in fear and disgust during exposure to threat-relevant stimuli in blood-injection-injury phobia

In the present study, participants (N=22) displaying marked fear of blood-injection-injury (BII) stimuli were provided 30 min of in vivo exposure to threat-relevant stimuli, during which time their fear and disgust levels were repeatedly assessed. Growth curve analyses were then conducted to examine the decay slopes in both fear and disgust and their relationship. Results indicated that exposure led to significant declines in fear and disgust across trials. However, the decay slope observed for fear was significantly greater than that for disgust. Further analyses revealed that the decline in fear across trials remained significant after accounting for the changes in disgust. However, the effect of trial on disgust was no longer significant after controlling for the reduction in fear. Global disgust sensitivity levels prior to exposure did not moderate the level of fear activation or fear reduction during exposure. BII-specific digust sensitivity was also not associated with initial levels of fear. However, levels of BII-specific disgust sensitivity were independently negatively associated with fear decline. Theoretical and clinical implications of the findings are discussed.

Specificity of disgust sensitivity in the prediction of behavioral avoidance in contamination fear

This study examined the specificity of disgust sensitivity in predicting contamination-related anxiety and behavioral avoidance. Participants high (n=26) and low (n=30) in contamination fear completed self-report measures of disgust sensitivity, contamination cognitions (overestimation of the likelihood and severity of contamination from everyday objects), anxiety, and depression. They then completed three randomly presented contamination-based behavioral avoidance tasks (BATs) that consisted of exposure to a used comb, a cookie on the floor, and a bedpan filled with toilet water. Results indicated that disgust sensitivity was significantly associated with anxious and avoidant responding to the contamination-related BATs. This association remained largely intact after controlling for gender, contamination fear group membership, anxiety, and depression. Contamination cognitions were also significantly related to BAT responses. However, this relationship was fully mediated by disgust sensitivity. These findings indicate that disgust sensitivity has a specific and robust association with contamination concerns commonly observed in obsessive compulsive disorder. The findings are discussed in the context of a disease-avoidance model.

Mechanisms of change in ERP treatment of compulsive hand washing: does primary threat make a difference?

The present study sought to examine patterns of habituation in exposure and response prevention (ERP) treatment of compulsive hand washing. Sub-clinical compulsive washers (n=27) with illness or non-illness primary threats were compared in order to detect potential differences in response to a single session of ERP. Changes in anxiety, disgust, and urge to wash were analyzed, and significant reductions in both anxiety and disgust were noted. Urge to wash significantly declined among washers primarily concerned with illness; among those concerned with non-illness threats, urge to wash did not significantly decline. Moreover, anxiety was found to decline when controlling for disgust and vice versa. Lastly, when both anxiety and disgust were entered into a model predicting changes in urge to wash, anxiety but not disgust predicted urge to wash for those with illness-related threats; for washers with non-illness threats, the findings were the reverse. Several clinical and theoretical implications are discussed.

Neurocircuitry of disgust and anxiety in obsessive-compulsive disorder: a positron emission tomography study

BACKGROUND

Disgust and fear are basic emotions that have different elicitors and expressions, and that appear to be mediated by different neurocircuits. Although obsessive-compulsive disorder (OCD) is classified as an anxiety disorder, disgust may be involved in its pathogenesis. Functional magnetic resonance imaging (fMRI) studies of disgust-inducing visual stimuli in OCD have suggested disorder specific alterations in brain activation during these tasks.

METHODS

Subjects with OCD and healthy controls (HC) underwent positron emission tomography (PET) brain scanning after injection of H(2) (15)O. During PET, subjects either watched slides designed to evoke feelings of disgust (OCD = 5, HC = 11), expected the delivery of an electrical shock (OCD = 11, HC = 13), or rested (OCD = 11, HC = 14). After the anticipatory anxiety and resting tasks, anxiety ratings, heart rate, and electrodermal measures were obtained. Statistical parametric mapping (SPM) was used to analyze regional cerebral blood flow (rCBF) data.

RESULTS

Comparison of OCD subjects with controls on differences in rCBF across the disgust-inducing and resting tasks showed that OCD was characterized by greater rCBF in the left insula. In OCD the disgust-inducing task increased right lateral orbitofrontal cortex rCBF compared to resting, whereas in controls there was no difference in rCBF between these tasks. Anxiety ratings, heart rate, and electrodermal activity increased during anticipatory anxiety in both groups, and comparison of rCBF in OCD subjects with controls in anticipatory anxiety versus resting state also found no significant differences.

CONCLUSIONS

OCD may be characterized by a disruption in disgust processing, such that there is a decrease in appropriate disgust (such as that evoked by observing disgust in others) and an increase in inappropriate disgust (such as that evoked by contamination stimuli). The insula may play a particularly important role in mediating such putative disruptions. The sample studied here was small, and further work is required to determine whether disgust-induced activation patterns in OCD are more apparent in specific subtypes of this disorder, whether they are specific to OCD, and whether they are normalized by treatment.

Serotonin--a link between disgust and immunity?

Immune systems maintain the integrity of organisms by recognising and attacking foreign substances and/or pathogens. However, immune defences can only take place following direct contact with threats. Disgust can prevent infection before contact with potential pathogens: we propose that disgust is an evolved nervous response to a signal reliably co-occurring with infectious environmental disease threats, which motivates behaviour leading to the avoidance of infection. We hypothesize that disgust and immunity form a defensive continuum with overlaps: disgust acts prior to contact with the infectious agent and prevents it from getting into the body; emesis (vomiting) gets it out once inside the gastrointestinal tract, before penetration of the body boundaries; and immunity expels or kills infectious threats following penetration of the body proper. We further propose that serotonin (5-hydroxytryptamine, 5-HT) might be the link between disgust and immunity. 5-HT plays a central role in the induction of the emetic reflex and is possibly involved in the development of learned aversion; it is also a signal used by immune cells and modulates both innate and acquired immunity. We therefore propose 5-HT might mediate the interaction between these two defensive mechanisms.

Common and distinct neural correlates of obsessive-compulsive and related disorders

Obsessive-compulsive disorder (OCD) often co-occurs with other anxiety disorders and a number of other disorders of similar phenomenology known as the "OCD spectrum" disorders. Neurobiologically, it is unclear how all these disorders relate to each other. The picture is further complicated by the clinical heterogeneity of OCD itself. This article reviews the literature on the common and distinct neural correlates of OCD, its symptom dimensions, and other anxiety and OCD spectrum disorders with the hope of providing a conceptual and heuristic framework to help understand the relationship between these phenomena.

Multimodal assessment of disgust in contamination-related obsessive-compulsive disorder

The present study utilizes multiple methods to examine the relationship between disgust and contamination-related obsessive-compulsive disorder (OCD) symptoms in an analogue sample. Questionnaire findings revealed that participants with high OCD contamination concerns showed stronger disgust sensitivity than did participants with low OCD contamination symptoms after controlling for negative affect. High OCD participants (N=30) also reported significantly more disgust than did low OCD participants (N=30) when exposed to a disgust-inducing video, whereas no significant between-group differences were detected on other negative emotional dimensions. Results from a series of disgust-specific behavioral avoidance tasks (BATs) revealed that high OCD participants demonstrated both less compliance and less approach behavior. Subsequent analysis also revealed that disgust sensitivity generally mediated avoidance on the BATs among high OCD subjects. High OCD participants also rated the BATs as more fearful and disgusting than did low OCD participants, with disgust generally emerging as the dominant emotional response. The results are consistent with a disgust-based, disease-avoidance approach in understanding contamination-related OCD themes.

Disgust, anxiety and fainting symptoms associated with blood-injection-injury fears: a structural model

The present study examines the structural relations between disgust sensitivity, anxiety symptoms, blood-injection-injury (BII) fears, and fainting symptoms associated with BII fears in 259 nonclinical participants. Results revealed that both disgust and BII fear were independent predictors of fainting symptoms. However, structural equation modeling revealed that the relation between disgust sensitivity and fainting was reduced to negative and non-significance when the path from BII fear to fainting was also introduced. Subsequent analysis indicated that the relation between disgust sensitivity and fainting symptoms was fully mediated by BII fear. It was also found that animal reminder disgust was related to fainting symptoms whereas core disgust was not. However, the relation between animal reminder disgust and fainting was also fully mediated by BII fear. Furthermore, anxiety symptoms did not add directly to the structural model predicting fainting associated with BII fears. Implications of these findings for better understanding the interaction of the emotional mechanisms that mediate fainting responses in BII phobia are discussed.

The neurocircuitry of obsessive-compulsive disorder and disgust

Recent evidence from human research has indicated that discrete regions of the brain control different basic emotions. Whether the recognition and formulation of emotions truly stem from compartmentalized systems or arise from a multidimensional framework has yet to be elucidated, however. Disgust is a basic emotion that has been hypothesized to constitute an evolutionary function of contamination and disease avoidance. Disgust involves the appraisal of objects and events for their potential role in contamination, and OCD conceivably involves a dysfunction of this appraisal process. Disgust sensitivity has been shown to be positively correlated with OCD and to significantly predict contamination fear. Likewise, functional imaging studies of OCD patients with contamination concerns demonstrate activation of the same neural regions with disgust-inducing pictures as symptom relevant stimuli. Therefore, the neurocircuits involved in disgust processing may be relevant to OCD and, in particular, the contamination subtype. This review focuses on describing what is known to date concerning the neurocircuitry of disgust, and its relevance to the apparent neurocircuitry of OCD.

The structural relation between disgust sensitivity and blood-injection-injury fears: a cross-cultural comparison of US and Dutch data

A growing body of literature has implicated the role of disgust sensitivity in blood-injection-injury (BII) phobia. The present study sought to extend this line of research by investigating the structural relation between Rozin et al.'s [(2000). Disgust. In M. Lewis, J.M. Haviland (Eds.), Handbook of emotions. New York: Guilford Publications.] theoretical model of core and animal reminder disgust as they relate to BII fears in US (N = 162) and Dutch (N = 260) samples. Using confirmatory factor analysis (CFA), the hypothesized relation between the theoretical model of disgust and BII fears demonstrated good model fit in both samples. Consistent with previous findings on the differential relation between core and animal reminder disgust and BII fears [de Jong, P. J., & Merckelbach H. (1998). Blood-injection-injury phobia and fear of spiders: Domain specific individual differences in disgust sensitivity. Personality and Individual Differences, 24, 153-158], structural equation modeling (SEM) provided support for a domain specific relationship in both samples: animal reminder disgust was specifically related to the BII latent factor, whereas core disgust was not. The clinical and research implications regarding the relationships between disgust and BII fears across cultures are discussed.

Disgust sensitivity and obsessive-compulsive symptoms in a non-clinical sample

Disgust sensitivity has been posited to play a role in the etiology and/or maintenance of obsessive-compulsive disorder (OCD); however, results of studies in this area have been mixed. We examined the relationship between specific domains of disgust sensitivity and specific OCD symptom patterns. One thousand and five undergraduate volunteers completed an internet battery of questionnaires including measures of OCD symptoms, depression, anxiety, and disgust sensitivity. Results indicated that even when controlling for depression and anxiety, several OCD symptom groups (checking, ordering, and washing) were associated with disgust sensitivity. Analysis of residuals, in which we controlled for every other OCD and disgust sensitivity domain for each paired comparison, indicated that the clearest relationship was between washing symptoms of OCD and disgust sensitivity toward hygiene-related stimuli. Examination of these items, however, raises questions about whether commonly accepted measures of disgust sensitivity might confound disgust with other forms of aversion. We discuss possible strategies for clarifying the degree to which fear and disgust are involved in OCD symptoms.

Using facial expressions as CSs and fearsome and disgusting pictures as UCSs: affective responding and evaluative learning of fear and disgust in blood-injection-injury phobia

Two experiments examine use of an evaluative conditioning (EC) paradigm in the acquisition of fear and disgust responding to neutral facial expressions. In Experiment 1, 60 participants were randomly assigned to one of three evaluative learning conditions in which neutral facial expressions were paired with fearsome, disgusting, or neutral pictures. No statistically significant differences were detected between the three conditions. However, significant differences emerged within subjects as post-exposure of fear and disgust ratings were higher among expressions that were paired with pictorial stimuli. Experiment 2 sought to examine if an analogue sample of BII phobics would be more susceptible than nonphobic controls to fear and disgust EC utilizing a similar experimental design, given the co-occurrence of fear and disgust in BII-phobic responding. Results failed to demonstrate an EC effect specific to the analogue phobic group, although both groups showed an evaluative shift toward disgust for those facial expressions paired with BII-relevant pictures. Consistent with previous findings, examination of picture rating data suggested that analogue BII phobics rated the BII pictures as significantly more disgusting than fearful. The role of EC processes and a priori expectancy biases in the associative learning of disgust in BII phobia is discussed.

The structure of disgust: domain specificity in relation to contamination ideation and excessive washing

The primary goal of the present study was to employ confirmatory factor analysis to compare two theoretical models regarding the factor structure of disgust (N=307). The two-factor model of Animal Reminder and Core disgust proposed by Rozin et al. (2000) demonstrated superior model fit over a one-factor model that has been implicated in prior research. However, contrary to theoretical predictions, categorizing Hygiene disgust as Core disgust rather than Animal Reminder disgust provided an overall better fit for the two-factor model. The second aim of the study was to investigate the relationship between the empirically derived two-factor model and contamination ideation and excessive washing using structural equation modeling. Findings indicated that the Contamination Ideation and Excessive Washing latent factor was specifically related to Core disgust (domain specific) and negatively related to Animal Reminder disgust. The relevance of these findings in the context of future research investigating the role of disgust in specific anxiety disorders is discussed.

Fear of contamination

Compulsive cleaning is an attempt to remove feelings of contamination that threaten one's physical health, mental health or ability to function socially. The fear of becoming contaminated can be complex, powerful, persistent and easily spread. Contamination is defined, the main types of contaminants set out and the characteristics of the fear are described. The distinction between normal and abnormal feelings of contamination is considered, and abnormal beliefs about contamination are analysed. Attention is drawn to the fact that contamination can occur without any physical contact, and the concept of mental pollution is used to elucidate this process. The causes and consequences of contamination fears are described, and some connections between fear and disgust are considered. The concept of cognitive co-morbidity is applied to an analysis of associations between the fear of contamination and obsessions, social fears and phobias. It is suggested that applying cognitive analyses and tactics may improve our ability to treat these powerful and tenacious fears.