A Meta-Analysis on the Efficacy of Exposure-Based Treatment in Anxiety Disorders: Implications for Disgust

Knowles K.A., Cox R.C., Armstrong T., Olatunji B.O.

A growing body of research has implicated disgust in various psychopathologies, especially anxiety-related disorders. Although the observed role of disgust in many disorders is robust, the mechanisms that may explain this role are unclear. Cutting-edge research in cognitive science has the potential to elucidate such mechanisms and consequently improve our understanding of how disgust contributes to the etiology and maintenance of psychopathology. In this qualitative review, we systematically assess cognitive bias mechanisms that have been linked to disgust and its disorders. This review suggests that disgust-related biases may be observed in memory, interpretation, judgment of expectancies, and attention, as well as at implicit levels. Of these cognitive domains, the most robust bias appears to be observed at the level of attention. However, reliable moderators of attentional biases for disgust have not yet been identified, and this bias has not been systematically linked to other levels of analysis. Despite these limitations, the available research indicates that attentional avoidance rather than orienting or maintenance may be the most characteristic of disgust. Attentional avoidance of disgust may have important implications for etiological and treatment models of disorders characterized by excessive disgust reactions. The implications for advancing such models are discussed in the context of a combined cognitive bias hypothesis.

Olatunji B.O., Armstrong T., Elwood L.

Research suggests that disgust may be linked to the etiology of some anxiety-related disorders. The present investigation reviews this literature and employs separate meta-analyses of clinical group comparison and correlational studies to examine the association between disgust proneness and anxiety-related disorder symptoms. Meta-analysis of 43 group comparison studies revealed those high in anxiety disorder symptoms reported significantly more disgust proneness than those low in anxiety symptoms. Although this effect was not moderated by clinical versus analogue studies or type of disorder, larger group differences were observed for those high in anxiety symptoms associated with contagion concerns compared to those high in anxiety symptoms not associated with contagion concerns. Similarly, meta-analysis of correlational data across 83 samples revealed moderate associations between disgust proneness and anxiety-related disorder symptoms. Moderator analysis revealed that the association between disgust proneness and anxiety-related disorder symptoms was especially robust for anxiety symptoms associated with contagion concerns. After controlling for measures of negative affect, disgust proneness continued to be moderately correlated with anxiety-related disorder symptoms. However, negative affect was no longer significantly associated with symptoms of anxiety-related disorders when controlling for disgust proneness. The implications of these findings are discussed in the context of a novel transdiagnostic model.

Armstrong T., Olatunji B.O.

Pavlovian fear conditioning provides a model for anxiety-related disorders, including obsessive-compulsive disorder (OCD). However, disgust is the predominant emotional response to contamination, which is a common theme in OCD. The present study sought to identify disgust conditioning abnormalities that may underlie excessive contamination concerns relevant to OCD. Individuals high and low in contamination concern (HCC, n = 32; LCC, n = 30) completed an associative learning task in which one neutral face (conditioned stimulus; CS+) was followed by a disgusting image (unconditioned stimulus; US) and another neutral face (CS-) was unreinforced. Following this acquisition procedure, there was an extinction procedure in which both CSs were presented unreinforced. The groups did not show significant differences in discriminant responding to the CSs following acquisition. However, following extinction, the HCC group reported less reduction in their expectancy of the US following the CS+, and also reported greater disgust to the CS+, compared to the LCC group. Increased disgust to the CS+ following both acquisition and extinction was correlated with increased symptoms of contamination-based OCD and increased disgust sensitivity. Additionally, disgust sensitivity mediated group differences in disgust responding to the CS+ at acquisition and extinction. Also, failure to adjust US expectancy in response to extinction partially mediated group differences in disgust to the CS+ following extinction. Together, these findings suggest that excessive contamination concerns observed in OCD may be related to difficulty inhibiting acquired disgust, possibly due to elevated disgust sensitivity that characterizes the disorder.

Sterne J.A., Hernán M.A., Reeves B.C., Savović J., Berkman N.D., Viswanathan M., Henry D., Altman D.G., Ansari M.T., Boutron I., Carpenter J.R., Chan A., Churchill R., Deeks J.J., Hróbjartsson A., et. al.

Non-randomised studies of the effects of interventions are critical to many areas of healthcare evaluation, but their results may be biased. It is therefore important to understand and appraise their strengths and weaknesses. We developed ROBINS-I (“Risk Of Bias In Non-randomised Studies - of Interventions”), a new tool for evaluating risk of bias in estimates of the comparative effectiveness (harm or benefit) of interventions from studies that did not use randomisation to allocate units (individuals or clusters of individuals) to comparison groups. The tool will be particularly useful to those undertaking systematic reviews that include non-randomised studies.

Ludvik D., Boschen M.J., Neumann D.L.

Disgust is an understudied but important emotion in various psychological disorders. Over the last decade, increasing evidence suggests that disgust is also present in various subtypes of obsessive-compulsive disorder (OCD), especially in contamination-related OCD (C-OCD). The treatment of choice for C-OCD is exposure with response prevention, originally designed to reduce fear-associated emotions thought to be acquired through Pavlovian conditioning (PC). However, disgust has been proposed to be acquired through evaluative conditioning (EC) and according to the referential model of this form of learning, there are functional differences between PC and EC that need to be considered in the treatment of disgust-related responses. Alternative strategies suggested by EC-based models include counterconditioning (contingent presentation of the CS with a US of opposite valence) and US revaluation (contingent presentation of the US with US of opposite valence). Drawing on the referential model, this paper reviews evidence for the effectiveness of each strategy to identify the most theoretically sound and empirically valid intervention to reduce disgust in C-OCD.

Podina I.R., Mogoase C., David D., Szentagotai A., Dobrean A.

Several meta-analyses indicate that cognitive-behavioral therapy (CBT) via electronic/technological devices or applications (i.e., eCBT) is an effective alternative to standard therapist-delivered CBT for anxious adults. However, we know little about the efficacy of eCBT interventions for anxious children and adolescents. The present meta-analysis set out to investigate the efficacy of eCBT in comparison to standard CBT or waitlist control for anxious children and adolescents. Eight randomized controlled studies (N = 404 participants) that targeted anxiety at post-intervention and follow-up were included in the analysis. The results indicated that eCBT was as effective as standard CBT (g = .295) and more effective than waitlist (g = 1.410) in reducing anxiety symptoms. Moderation analyses revealed that anxious children and adolescents benefited the most from eCBT in the minimal therapist involvement condition (g = 2.682) in contrast to the significant therapist involvement group (g = .326). Furthermore, older participants seemed to extract greater clinical benefits from eCBT in contrast to younger participants (slope = .514). Current eCBT interventions for anxious children and adolescents appear to be promising, but require further investigation.

Badour C.L., Feldner M.T.

Emerging evidence identifies disgust as a common and persistent reaction following sexual victimization that is linked to posttraumatic stress disorder (PTSD). Importantly, evidence suggests that compared with fear, disgust may be less responsive to repeated exposure, which may have implications for the treatment of PTSD. The current study sought to fill a gap in the existing literature by examining reductions in sexual trauma cue-elicited disgust and anxiety upon repeated imaginal exposure.Seventy-two women with a history of sexual victimization completed a single laboratory-based session that involved repeated imaginal exposure to idiographic disgust- and fear-focused sexual trauma scripts.Results demonstrated that although anxiety and disgust declined at similar rates across exposure trials (t = -.24, p = .81), ratings of disgust (B0 = 61.93) were elevated compared with ratings of anxiety at initiation (B0 = 51.03; t = 4.49, p < .001) of exposure even when accounting for severity of PTSD symptoms. Moreover, change in disgust significantly predicted improvement in script-elicited PTSD symptoms across the course of exposure for individuals exhibiting significant decline in anxiety (B = .006, t = 2.00, p = .048). Change in script-elicited PTSD symptoms was minimal (and was not predicted by the decline in disgust) for individuals exhibiting less change in anxiety (B = -.002, t = -0.46, p = .65).These results add to an increasing literature documenting the importance of disgust in the development, maintenance, and treatment of sexual-trauma-related PTSD. (PsycINFO Database Record

von Hippel P.T.

Estimated effects vary across studies, partly because of random sampling error and partly because of heterogeneity. In meta-analysis, the fraction of variance that is due to heterogeneity is estimated by the statistic I2. We calculate the bias of I2, focusing on the situation where the number of studies in the meta-analysis is small. Small meta-analyses are common; in the Cochrane Library, the median number of studies per meta-analysis is 7 or fewer. We use Mathematica software to calculate the expectation and bias of I2. I2 has a substantial bias when the number of studies is small. The bias is positive when the true fraction of heterogeneity is small, but the bias is typically negative when the true fraction of heterogeneity is large. For example, with 7 studies and no true heterogeneity, I2 will overestimate heterogeneity by an average of 12 percentage points, but with 7 studies and 80 percent true heterogeneity, I2 can underestimate heterogeneity by an average of 28 percentage points. Biases of 12–28 percentage points are not trivial when one considers that, in the Cochrane Library, the median I2 estimate is 21 percent. The point estimate I2 should be interpreted cautiously when a meta-analysis has few studies. In small meta-analyses, confidence intervals should supplement or replace the biased point estimate I2.

Badour C.L., Feldner M.T., Babson K.A., Blumenthal H., Dutton C.E.

Disgust and mental contamination (or feelings of dirtiness and urges to wash in the absence of a physical contaminant) are increasingly being linked to traumatic event exposure and posttraumatic stress (PTS) symptomatology. Evidence suggests disgust and mental contamination are particularly relevant to sexual assault experiences; however, there has been relatively little direct examination of these relations. The primary aim of the current study was to assess disgust and mental contamination-based reactivity to an individualized interpersonal assault-related script-driven imagery procedure. Participants included 22 women with a history of traumatic sexual assault and 19 women with a history of traumatic non-sexual assault. Sexual assault and PTS symptom severity predicted greater increases in disgust, feelings of dirtiness, and urges to wash in response to the traumatic event script. Finally, assault type affected the association between PTS symptom severity and increases in feelings of dirtiness and urges to wash in response to the traumatic event script such that these associations were only significant among sexually assaulted individuals. These findings highlight the need for future research focused on elucidating the nature of the relation between disgust and mental contamination and PTS reactions following various traumatic events.

Mason E.C., Richardson R.

There is now a significant body of work which indicates that excessive disgust responses play a crucial role in certain anxiety disorders. In addition, emerging evidence suggests that disgust may not be effectively reduced by exposure therapy. Because of this, there is a need to arm clinicians with additional therapeutic tools to target maladaptive disgust responses. This study reviews potential strategies that may be useful in reducing disgust in the context of anxiety disorders. This review is intended to provide a useful starting point to inform clinicians and suggest possible future research directions. Ultimately, by ameliorating dysfunctional and distressing emotions other than fear that are prominent in certain anxiety disorders, such as disgust, treatments for anxiety disorders may be improved.

Badour C.L., Bown S., Adams T.G., Bunaciu L., Feldner M.T.

Emerging evidence has documented comorbidity between posttraumatic stress disorder (PTSD) and obsessive-compulsive disorder (OCD) among individuals with a history of traumatic events. There is growing recognition of the importance of disgust in each of these conditions independently. No study, however, has examined the potential role of disgust in these conditions following traumatic event exposure. The current study examined the unique role of peritraumatic fear, self-focused disgust, and other-focused disgust in predicting posttraumatic stress symptoms and contamination-based OC symptoms among 49 adult women (M(age)=28.37, SD=13.86) with a history of traumatic interpersonal victimization. Results demonstrated that intensity of peritraumatic self-focused disgust was significantly related to contamination-based OC symptoms while peritraumatic fear and other-focused disgust were related to posttraumatic stress symptoms. These results highlight the need for future research aimed at elucidating the nature of the association between disgust experienced during traumatic events and subsequent psychopathology.

Olatunji B.O., Ciesielski B.G., Wolitzky-Taylor K.B., Wentworth B.J., Viar M.A.

Despite growing evidence implicating disgust in the etiology of blood-injection-injury (BII) phobia, the relevance of disgust for exposure-based treatment of BII phobia remains largely unknown. Individuals with BII phobia were randomly assigned to a disgust (view vomit videos) or neutral activation (view waterfall videos) condition. They were then exposed to 14 videotaped blood draws, during which fear and disgust levels were repeatedly assessed. Participants then engaged in a behavioral avoidance test (BAT) consisting of exposure to threat-relevant stimuli. Examination of outcome comparing the identical first and last blood-draw clips revealed that fear and disgust toward blood draws was significantly reduced in both groups. Disgust levels were also found to be more intense for the video stimuli relative to fear levels whereas the opposite was true for BAT stimuli. Contrary to predictions, the disgust induction did not enhance reductions in negative responses to the target video or reduce behavioral avoidance. Growth curve analyses did show that individuals with BII phobia exposed to the disgust induction showed greater initial fear levels during repeated exposure than those in the neutral condition. However, this effect was not consistently observed across different analytic approaches. Changes in fear during exposure were also found to be independent of changes in disgust but not vice versa, and greater initial fear levels during repeated exposure to threat was associated with fear and disgust levels during the BAT. The implications of these findings for conceptualizing the role of disgust in etiology and treatment of BII phobia are discussed.

Rachman S., Shafran R., Radomsky A.S., Zysk E.

It has been proposed that the judicious use of safety behaviour can facilitate improvements in the acceptability of cognitive behaviour therapy (CBT). It was decided to explore the possibility of facilitating CBT by introducing a form of safety behaviour. We sought to assess the degree to which Exposure plus Safety Behaviour (E + SB) is an effective intervention for contamination fears.A comparison was made between the effects of a control condition (Exposure and Response Prevention; ERP) and an experimental condition (Exposure plus Safety Behaviour; E + SB) in which each exposure to a contaminant was followed by the use of a hygienic wipe in a sample of (n = 80) undergraduate students. In session one, each participant touched a confirmed contaminant 20 times. After each exposure participants were asked to report their feelings of contamination, fear, disgust, and danger. In the second session, two weeks later, the same procedure was carried out for a further 16 trials.The ERP and the E + SB conditions both produced large, significant and stable reductions in contamination. Significant reductions in fear, danger and disgust were also reported in both conditions.The treatment was provided to an analogue sample and over two sessions.The use of hygienic wipes, the safety behaviour used in this experiment, did not preclude significant reductions in contamination, disgust, fear and danger. If it is replicated and extended over a longer time-frame, this finding may enable practitioners to enhance the acceptability of cognitive behavioural treatments and boost their effectiveness.

Olatunji B.O., Tart C.D., Ciesielski B.G., McGrath P.B., Smits J.A.

A growing body of research has implicated disgust as a potential risk factor for the development and maintenance of obsessive-compulsive disorder (OCD). The first aim of the present study was to determine whether related, yet distinct, disgust vulnerabilities are endorsed more strongly by individuals with OCD than by those with another anxiety disorder. The second aim was to examine the unique contributions of changes in disgust to symptom improvement observed with exposure-based treatment for OCD. In study 1, individuals with OCD, generalized anxiety disorder (GAD), and nonclinical controls (NCCs) completed a measure of disgust propensity and disgust sensitivity. Compared to NCCs and individuals with GAD, those with OCD more strongly endorsed disgust propensity. However, individuals with OCD did not significantly differ from individuals with GAD in disgust sensitivity, although both groups reported significantly higher disgust sensitivity levels compared to NCCs. Study 2 comprised mediation analyses of symptom improvement among individuals with OCD and revealed that decreases in disgust propensity over time mediated improvement in OCD symptoms, even after controlling for improvements in negative affect. The implications of these findings for conceptualizing the role of disgust in the nature and treatment of OCD are discussed.

Curtis V., de Barra M., Aunger R.

Disgust is an evolved psychological system for protecting organisms from infection through disease avoidant behaviour. This ‘behavioural immune system’, present in a diverse array of species, exhibits universal features that orchestrate hygienic behaviour in response to cues of risk of contact with pathogens. However, disgust is also a dynamic adaptive system. Individuals show variation in pathogen avoidance associated with psychological traits like having a neurotic personality, as well as a consequence of being in certain physiological states such as pregnancy or infancy. Three specialized learning mechanisms modify the disgust response: the Garcia effect, evaluative conditioning and the law of contagion. Hygiene behaviour is influenced at the group level through social learning heuristics such as ‘copy the frequent’. Finally, group hygiene is extended symbolically to cultural rules about purity and pollution, which create social separations and are enforced as manners. Cooperative hygiene endeavours such as sanitation also reduce pathogen prevalence. Our model allows us to integrate perspectives from psychology, ecology and cultural evolution with those of epidemiology and anthropology. Understanding the nature of disease avoidance psychology at all levels of human organization can inform the design of programmes to improve public health.

Moran E., McKay D.

Lafortune D., Lapointe V.A., Dubé S., Bonneau J.

Abstract Background Sexual dysfunctions impair the intimate relationships of up to one-third of the population. Virtual reality (VR) offers innovative treatment options for both mental and sexual disorders, such as female orgasmic disorder and erectile disorder. Sexual aversion disorder (SAD)—the anxiety, disgust, and avoidance of sexual contexts—is a chronic condition commonly treated with anxiety-reducing strategies, such as exposure-based therapy. Despite exposure’s efficacy in reducing SAD symptoms, VR exposure therapy’s (VRET) effectiveness remains unexplored for this condition. Aim This proof-of-concept study examines the acceptability, adequacy, and clinical effects of a VRET’s simulation protocol for SAD. Methods In the laboratory, 15 adults suffering from SAD (Mage = 35.00; SD = 11.36) viewed 15 virtual sexual scenarios of increasing intensity (eg, flirting, nudity, genital stimulation) adjusted to their sexual preferences and gender identities. Outcomes Levels of anxiety, disgust, and catastrophizing beliefs were measured throughout the scenarios using standard self-report measures. Participants also completed validated questionnaires on sexual presence and simulation realism, as well as open-ended questions on scenarios’ representativeness and adequacy immediately after immersion. Six months after the laboratory visit, participants completed a negative effects questionnaire and were screened for SAD symptoms again. Repeated-measures ANOVAs and descriptive analyses were performed. Results Levels of anxiety and disgust significantly increased with the intensity of sexual scenarios. Catastrophizing levels were high and tended to augment with increasing exposure levels. A significant reduction in symptoms of SAD was found from pre-simulation to the 6-month follow-up assessment. Sexual presence and realism scores were moderate. Qualitative assessment revealed that all participants reported the sexual scenarios were representative of real-life situations that tend to elicit SAD symptoms for them. Reported negative effects were generally mild. Clinical Implications This proof-of-concept study suggests that VRET may have the potential to elicit self-reported emotional and cognitive manifestations of SAD (sex-related anxiety, disgust, and catastrophizing), while also hinting at its acceptability, adequacy, and benefits in alleviating SAD symptoms. Strengths & Limitations While this study marks the first exploration of the clinical relevance of gender-inclusive virtual sexual scenarios for SAD, its design and sample composition may impact observed effects and the generalizability of findings. Conclusion This study invites future clinical trials to assess VRET efficacy for SAD.

Mitchell B.J., Olatunji B.O.

Anxiety disorders have long been conceptualized as disorders of fear, while other emotions have largely been overlooked. However, an emerging literature has increasingly implicated disgust in certain anxiety-related disorders, including obsessive-compulsive disorder, specific phobias (e.g., spider phobia), health anxiety, and post-traumatic stress disorder. Roughly two decades of research has accumulated evidence identifying various mechanisms linking disgust-related phenomena to these disorders. In the present “State of the Science” review, we sought to summarize the current state of the literature with respect to disgust-related mechanisms in anxiety disorders, including trait-level vulnerabilities (e.g., disgust proneness), cognitive processes (e.g., biases of attention and memory), and associated learning mechanisms (e.g., evaluative conditioning). Research in these areas has revealed important ways in which disgust differs from fear-related phenomena, which have important treatment implications. From there, we sought to summarize research on laboratory interventions that attempt to target and attenuate disgust, as well as the early research on formal cognitive-behavioral treatments that integrate disgust-related interventions for anxiety disorders. Although the past two decades of research have revealed important insights related to the role of disgust in psychopathology, much remains to be learned in this area. We propose some future directions, emphasizing the importance of a guiding framework that highlights studying disgust-related mechanisms across different levels of analysis.

Franklin M.E., Schwartz R.A.

Pediatric OCD is associated with substantive symptoms, impairment across multiple domains and, if left untreated, clinically significant dysfunction extending into adulthood. Fortunately, the efficacy and effectiveness of several forms of treatment have now been established, the most studied of which is cognitive behavioral therapy (CBT) involving exposure plus response prevention (ERP). Our review describes this literature in detail, and also covers the search for predictors and moderators of outcome which may help identify patient subgroups at risk for partial or non-response (treatment-resistant). ERP is efficacious both alone and in combination with pharmacotherapy with serotonin reuptake inhibitors (SRIs) and appears to retain its benefits beyond the context of the academic medical centers where the protocols were developed and tested initially. However, there are still some patients who do not respond fully to the first-line interventions. Data on several potential candidates for prediction and moderation is reviewed, factors that limit the utility of the extant literature are described, and new initiatives are discussed which may allow the field to move forward in informing the development of the algorithms necessary for the application of the principles of precision medicine in pediatric OCD. Efficacious treatments for pediatric OCD have been identified, but response to these first-line interventions is neither universal nor complete. Issues in play that limit access to efficacious forms of care including ERP at present are described, and potential solutions are offered to address current barriers to improving empirically supported interventions and increasing treatment access.

Jones H.R., Lorenz T.K.

Prior research consistently shows disgust propensity and/or state disgust correlated with lower sexual arousal; however, this work has largely excluded women with sexual trauma histories. We tested competing models of the effects of disgust on sexual arousal in women with sexual trauma histories: heightened avoidance of sexual stimuli vs. heightened affective antagonism between pathogen disgust and sexual arousal. Seventy-seven women (45 with an unwanted sexual contact history, 32 without) completed an online survey, avoidance task, and sexual arousal task following a pathogen disgust or neutral prime. We conducted preregistered and exploratory analyses of women’s self-reported arousal and behavioral avoidance of the sexual aspects of stimuli. Women who reported more unwanted sexual contact had lower subjective sexual arousal in response to sexual stimuli, particularly following a disgust prime. There was evidence of an interaction such that unwanted sexual contact history amplified the effects of disgust propensity, contributing to greater avoidance of sexual stimuli. Women with a history of forced sex had significantly higher behavioral avoidance of sexual stimuli, even when accounting for exposure to other types of unwanted sexual contact and history of pathogen exposure. Cumulative type and frequency of sexual assault may influence women’s sexual disgust, avoidance, and arousal. Lifetime history of pathogen exposure may not predict sexual disgust. Clinically, our results suggest that sexual avoidance may be a beneficial target of intervention when addressing sexual arousal concerns of survivors of unwanted sex, above and beyond reduction of sexual disgust responses.

Breiner C.E., Miller M.L., Hormes J.M.

Eating disorder (ED) treatment is notoriously inaccessible due to geographic, financial, and/or time barriers. The current study proposes a novel treatment for avoidant/restrictive food intake disorder (ARFID) to increase access to care for this novel ED. ARFID Parent Training Program (ARFID-PTP) is a two-session, virtual treatment utilizing evidence-based components for pediatric ARFID. Participants (n = 7) ages 5–12 and their parents completed an intake session, two sessions of treatment, end-of-treatment measures, and 4-week follow-up measures. Acceptability was assessed via the CEQ-C and satisfaction questions provided at end-of-treatment. Feasibility was assessed via recruitment and retention rates, treatment adherence, and need for a booster session (e.g., problem-solving session) at 4-week follow-up. Overall, ARFID-PTP was considered an acceptable treatment approach; however, markers of feasibility, such as treatment nonadherence (low completion of daily food exposures), indicate further testing should implement modifications to treatment. We propose modifications to address feasibility concerns with the goal of continuing to assess ARFID-PTP in a randomized controlled trial.

Mitchell B.J., Coifman K.G., Olatunji B.O.

Disgust can be acquired via evaluative conditioning; a process by which a neutral stimulus (conditioned stimulus; CS) comes to be evaluated as disgusting due to its pairing with an inherently disgusting stimulus (unconditioned stimulus; US). Research has shown that conditioned disgust responses are resistant to extinction which may have implications for disorders (i.e., contamination-based obsessive-compulsive disorder, specific phobias, and post-traumatic stress disorder) in which heightened disgust has been implicated. Importantly, extinction is the primary mechanism by which exposure therapies are thought to achieve symptom reduction for these disorders. Exposure therapies were originally modeled on fear extinction, whereas disgust extinction was largely overlooked until recently. Accordingly, differences in the degree to which learned disgust and fear can be attenuated via extinction learning remains unclear. The present investigation was a meta-analysis directly comparing the degree of extinction of conditioned disgust (n = 14) and conditioned fear (n = 14) in laboratory paradigms. Extinction was operationalized as the standardized mean difference (SMD) in evaluative ratings between the CS+ (the CS paired with the US) and CS- (the unpaired CS) after extinction training. Results of a subgroup analysis indicated that disgust (SMD = 0.52) was significantly more resistant to extinction than fear (SMD = 0.37). Additionally, a series of meta-regression analyses indicated that extinction was not influenced by important study characteristics (e.g., sex, age, number of conditioning and extinction trials). The findings suggest that extinction-based approaches may be less effective at attenuating learned disgust and research is needed to better optimize treatments for disgust-related disorders.

Breiner C.E., Miller M.L., Hamilton A.L., Cruz Garcia S., Sanzari C.M., Hormes J.M.