Disgust as a transdiagnostic index of mental illness: A narrative review of clinical populations

Disgust is a basic emotion of rejection, providing an ancestral defensive mechanism against illness. Based on research that documents altered experiences of disgust across several psychopathological conditions, we conducted a narrative review to address the hypothesis that altered disgust may serve as a transdiagnostic index of mental illness. Our synthesis of the literature from past decades suggests that, compared to healthy populations, patients with mental disorders exhibit abnormal processing of disgust in at least one of the analyzed dimensions. We also outline evidence of alterations in brain areas relevant to disgust processing, such as the insula and the interconnected limbic network. Overall, we provide preliminary support for the hypothesis that altered disgust processing may serve as a transdiagnostic index of mental illness.

A brief measure of disgust propensity

In the context of large-scale surveys, pre-screening or longitudinal studies, researchers may be faced with the choice of using a brief measure of disgust propensity (DP: the general tendency to respond with the emotion of disgust to any given situation) or using no measure at all. The goal of the present study was to develop and validate such a short scale based on the Questionnaire for the Assessment of Disgust Propensity (QADP); Schienle et al., 2002). The participants (n = 1367; 80% female; mean age = 28 years) completed the QADP, and scales on disgust sensitivity and self-disgust. Brain structural data and disgust rating data were available for subsets of the total sample. Factor analysis revealed a five-factor structure of the QADP. A total of 10 items (two items for each factor) with the highest item-total correlations were selected. The resulting five-factor QADP (Cronbach’s alpha = .76) covers a broad range of disgust domains. The short QADP is correlated with the original questionnaire (r = .90), disgust sensitivity, disgust ratings for gustatory, olfactory and visual disgust elicitors, and volume in the insular cortex (a brain region involved in disgust processing). For future investigations, the QADP_brief can be a useful tool for assessing DP with high time efficiency.

Self-disgust in Patients with Dermatological Diseases

BACKGROUND

Dermatological diseases can be associated with symptoms such as oozing pus, weeping, and/or bleeding, which represent primary disgust elicitors. This study examined the role of self-disgust in people with different skin conditions (e.g., hidradenitis suppurativa, psoriasis, lichen sclerosus).

METHODS

A self-selected sample of 200 dermatology patients completed questionnaires for the assessment of self-disgust, experienced stigmatization, symptoms of depression, anxiety, and somatization. Multiple regression analysis and mediation analysis were computed to examine the relationship between self-disgust and the other selected variables.

RESULTS

Sixty-four percent of the patients reported elevated self-disgust. Sex, age, depression, and perceived stigmatization were predictors of self-disgust. Depression mediated the relationship between stigmatization (e.g., staring by others) and self-disgust.

CONCLUSIONS

This study points to the important role of self-disgust in dermatological conditions. Public health programs to counteract stigmatization of patients with skin diseases as well as therapy approaches that help decrease patients' self-disgust and increase self-acceptance are urgently needed.

Self-Disgust and Its Relationship With Lifetime Suicidal Ideation and Behavior

Abstract. Background: The emotion disgust is typically directed toward stimuli in the external environment, but sometimes people develop self-directed disgust responses. Aims: The current questionnaire study focused on the role of self-disgust in lifetime suicidal ideation and behavior. Method: A total of 1,167 individuals participated in an Internet-based survey containing self-report measures of self-disgust, externally directed disgust proneness, coping styles, diagnoses of mental disorders, and suicide risk. Hierarchical regression analyses as well as mediation analyses were computed. Results: Self-disgust was the most relevant predictor of suicide risk among the assessed variables. Self-disgust was negatively associated with the use of support by others, and positively associated with evasive coping (self-blame, venting, denial), which in turn was positively associated with suicidality. Limitations: This cross-sectional study provided information on the relationship between self-disgust and suicidality in a self-selected sample. Longitudinal studies are warranted. Conclusion: Future studies are required to replicate these findings. Additionally, stronger research designs are needed in order to investigate whether self-disgust should be targeted in suicide prevention programs and interventions.

Questionnaire for the Assessment of Self-Disgust: The psychometric testing among mental disorders in China

Research on self-disgust is relevant to psychopathologic tendencies because it has been shown to play a critical role in several mental disorders. Examining self-disgust and exploring its role in mental health are significant goals. The purpose of this study was to translate the Questionnaire for the Assessment of Self-Disgust (QASD) into Chinese and evaluate its validity and reliability. The translation and validation of the QASD were guided by the World Health Organization's Process of Translation and Adaptation of Instruments. Three phases were undertaken: (a) professional translation and expert panel review, (b) pretesting, and (c) psychometric evaluation. The psychometric evaluation was tested among 1,068 patients who were recruited from two psychiatric hospitals and three psychological clinics of tertiary hospitals. In this study, multigroup confirmatory factor analysis (CFA) supported the two-factor structure of the original QASD construct. Measurement invariance showed that the QASD is invariant across the patients with heterogeneous mental health diagnoses. The correlation of QASD with the Self-Esteem Scale (SES) and the Trait Anger Scale (TAS) showed that it has good convergent validity and discriminative validity. Internal consistency and test-retest yielded acceptable results. Thus, the findings suggest that the Chinese version of the QASD is a reliable and valid instrument with adequate psychometric properties for assessment of self-disgust among patients with mental disorders in China.

Visual symptom provocation in skin picking disorder: an fMRI study

Skin-picking disorder (SPD) is a common mental disorder characterized by recurrent and excessive picking of dermatological irregularities. Different disorder models have been developed to explain this behavior, but empirical evidence is still scarce. One model (the disgust-related disease avoidance model) suggests that SPD might be understood as pathological grooming elicited by skin imperfections that singal possible infection. Twenty-five women with SPD and 19 matched controls viewed and rated images depicting skin irregularities and smooth skin during functional magnetic resonance imaging. The participants did not engage in picking behavior. Relative to controls, SPD patients reported more disgust and urge to pick when looking at skin irregularities. This was accompanied by greater activation in the insula and amygdala, and stronger insula-putamen coupling. Disgust feelings elicited by viewing skin irregularities were positively correlated with activation of the insula and the putamen, in the clinical group. On personality questionnaires, the SPD patients reported elevated self-loathing and problems in regulating their disgust feelings. The current study provides first evidence for altered disgust processing in SPD patients.

Hyposmia and Disgust: Gender-Specific Effects

Reduced olfactory function is associated with altered trait disgust in men. This study sought to determine whether hyposmic women show similar changes in disgust responsiveness. We compared patients with hyposmia (25 men, 23 women) and 50 normosmic individuals (25 men, 25 women) with regard to their tendency to experience disgust across different disgust domains (disgust proneness), their self-disgust and their tendency to perceive their own disgust feelings as difficult to control and embarrassing (disgust sensitivity). We replicated the finding that male patients reported elevated self-disgust and disgust proneness toward a specific disgust domain (poor hygiene), whereas female patients obtained comparable disgust scores as the female control group. Both men and women of the patient group indicated disgust regulation difficulties in social contexts. In conclusion, we found greater changes in trait disgust in men with hyposmia. This gender-specific effect, which might be a result of more efficient compensatory behaviors in women, needs further investigation.

Symptom severity and disgust-related traits in borderline personality disorder: The role of amygdala subdivisions

The majority of morphometric studies on borderline personality disorder (BPD) found that diagnosed patients have a reduced amygdala volume. We sought to extend this finding by focusing on amygdala subdivisions (centromedial, laterobasal, superficial) and their association with symptom severity and disgust-related traits. Additional disorder-/disgust-relevant regions (insula, somatosensory cortex) were also investigated. We compared structural imaging data from 25 female BPD patients and 25 healthy women via voxel-based morphometry. Scores on self-report measures for symptom severity, disgust proneness, and self-disgust were correlated with gray matter volume (GMV) of regions of interest. Relative to controls, BPD patients had more GMV in the laterobasal amygdala. The volume of this region was positively correlated with symptom severity. In contrast, GMV of the centromedial amygdala showed a negative correlation with symptom severity. The degree of reported self-injury and self-disgust correlated negatively with the volume of the secondary somatosensory cortex (SII). Our data point to a differential contribution of amygdala subdivisions to symptom severity in BPD. Future longitudinal studies should focus on these subregions and possible volume changes during the course of the disorder. The meaning of altered SII volume for dysfunctional auto-aggressive behavior needs further investigation.

Effects of personal space intrusion in affective contexts: an fMRI investigation with women suffering from borderline personality disorder

The amygdala and the parietal cortex play a key role in the neural representation of personal space. Although the concept of personal space is clinically very relevant for borderline personality disorder (BPD), especially in affective contexts, it has not been investigated thus far with functional magnetic resonance imaging (fMRI). In this fMRI study, 25 female BPD patients and 25 healthy women were exposed to photos of angry, disgusted and neutral facial expressions. All stimuli were once shown as still photos, and once were zoomed-in in order to simulate intrusion into one's own personal space. Approaching faces generally provoked activation of the amygdala and the somatosensory cortex. BPD patients showed an increased activation within both regions, but only toward approaching disgusted faces. Their amygdala activation in this specific condition positively correlated with self-disgust scores. Moreover, the clinical group indicated an enhanced personal distance preference, which was associated with parietal activation. The present study revealed altered personal space processing of BPD patients, especially in situations that relate to social contexts involving disgust. Future studies should focus on the temporal stability of personal space processing during the natural course of BPD as well as during therapy.