Evaluating the mediating effects of perceived vulnerability to disease in the relation between disgust and contamination-based OCD

Preliminary Examination of Sympathetic Magic as a Psychological Endophenotype for Obsessive-Compulsive Disorder

Although sympathetic magic (SM) beliefs (i.e., irrational understanding of contagion transmission) are observed in obsessive-compulsive disorder (OCD), it is unclear if such beliefs are psychological endophenotypes. Furthermore, predictors of SM beliefs in OCD remain unknown. Accordingly, the present study examined whether SM beliefs function as an endophenotype for OCD and whether perceived vulnerability to disease (PVD) contributes to SM beliefs. A sample of 30 individuals with OCD, 26 first-degree relatives, and 25 age-matched healthy controls completed self-report questionnaires and a SM task where we touched a clean pencil to a "contaminated" toilet, and rated the degree to which the pencil was contaminated. A second pencil was touched to the first pencil and was then rated. This process was continued for 12 pencils (12 degrees of removal from contagion). Results revealed no significant differences in the extent to which the three groups perceived a "chain of contagion" (i.e., contamination slopes) for the successive degrees of removal from the original contagion. However, the OCD group reported significantly less contamination reduction on the task, a group difference that was mediated by PVD. These findings suggest that although SM beliefs may not be an OCD endophenotype, such beliefs may derive from a PVD.

State and Trait Disgust Uniquely Predict Avoidance in Contamination Fear: Specificity of Disease-Specific and Nonspecific Individual Differences

Although behavioral avoidance is observed among those with heightened contamination concerns, the extent to which such avoidance is best predicted by state and/or trait characteristics is unclear. Furthermore, while disgust proneness is a disease-specific trait that has been shown to predict avoidance among those with symptoms of contamination-based obsessive-compulsive disorder (OCD), it is unclear if other disease-specific traits may also serve a similar function. In the present study, contamination-fearful participants (N = 89) first completed self-report measures of disease-specific (disgust proneness, health anxiety, perceived vulnerability to disease) and disease-nonspecific (intolerance of uncertainty, trait anxiety) traits. They then completed a 16-step behavioral approach task (BAT) with increasing likelihood of contagion in a public restroom and provided ratings of state disgust and state anxiety at each step. Bayesian hierarchical logistic regression showed that state disgust, but not state anxiety, at a given step was associated with avoidance on the next step. Furthermore, disgust proneness was the only trait associated with avoidance on the BAT. A significant interaction between disgust proneness and BAT step completed in the public restroom was also found. Examination of this interaction suggests that intermediary, but not initial and latter, steps of the BAT differentiate those high and low in disgust proneness. These findings suggest that state and trait disgust uniquely drive behavioral avoidance among those with contamination concerns commonly observed in OCD.

Relationship between disgust and orthorexia nervosa and psychometric properties of the Italian Dusseldorf orthorexia scale in a general population sample

BACKGROUND

It remains unclear among clinicians and researchers whether orthorexia nervosa (ON) is a part of the obsessive-compulsive disorder spectrum or eating disorders. Disgust seems to be a shared psychopathological factor in these clinical presentations, indicating a potentially crucial role in ON. On the other hand, numerous psychometric tools have been developed to evaluate ON. The Dusseldorf Orthorexia Scale (DOS) was recently validated in an Italian sample. However, the study's primary limitation was that the scale was only administered to undergraduate university students. This study aimed to investigate the psychometric properties (including factorial structure, reliability, and measurement invariance conditional on sex) of the Italian version of the DOS (I-DOS) on a sample from the general population. Additionally, the study sought to determine the nomological validity of the I-DOS by examining its relationship with disgust sensitivity.

METHODS

A sample of 521 participants took part in this study and completed a battery that assessed ON and disgust sensitivity. To assess the I-DOS structure, reliability, and measurement invariance we respectively conducted confirmatory factor analysis (CFA), computed McDonalds's omega, and performed hierarchical series of multigroup CFAs. Then, we tested the relationship between ON and disgust sensitivity.

RESULTS

CFA confirmed the unifactorial model of I-DOS and it respected the configural, metric, and strict invariance while a partial scalar invariance was achieved. It also showed good reliability with an omega of 0.87. In addition, we found a positive relationship between ON and disgust sensitivity, thus confirming the nomological validity of I-DOS.

CONCLUSIONS

Our findings suggest that the Italian version of the Dusseldorf orthorexia scale (I-DOS) exhibits strong psychometric properties and can be an effective instrument for assessing ON in a general population sample. Notably, the most significant and innovative outcome was the positive correlation between ON and disgust sensitivity. As disgust has been linked to other clinical presentations, this preliminary result could serve as a foundation for future research exploring this phenomenon in greater detail.

Obsessive-Compulsive Symptom Dimensions and Their Relationships with Obsessive Beliefs: A Structural Equation Modeling Analysis

Dysfunctional beliefs are central in the development and maintenance of obsessive-compulsive disorder (OCD) as well as its treatment. Yet, research suggests that not all dysfunctional beliefs are equally important for each of the symptom dimensions of OCD. However, results are inconsistent in that studies contradict each other regarding the associations between specific symptom dimensions and belief domains. The aim of the present study was to clarify which belief domain is specifically associated with which OCD symptom dimension. Results could help to tailor treatments more specifically to the patient's OCD symptom dimension. In- and outpatients with OCD (N = 328; 43.6% male and 56.4% female) filled out questionnaires on symptom dimensions of OCD (Obsessive-Compulsive Inventory Revised) and dysfunctional beliefs (Obsessive Beliefs Questionnaire). A structural equation model analysis was conducted to identify the associations between dysfunctional beliefs and symptom dimensions. Our results showed that perfectionism/intolerance of uncertainty was associated with hoarding and symmetry/ordering, (2) overestimation of threat/inflated responsibility was associated with checking compulsions, and (3) importance of thoughts/control of thoughts was associated with obsessing. These results were largely supported by a backward selection. Our results demonstrated associations of specific dysfunctional beliefs and specific OCD symptom dimensions. However, future studies are necessary to replicate these findings with other measures (e.g., clinician ratings).

The Association of Perceived Vulnerability to Disease with Cognitive Restraint and Compensatory Behaviors

Individual differences exist in perceived vulnerability to disease (PVD). PVD is associated with negative responses (e.g., disgust) towards individuals with obesity and heightened sensitivity regarding personal appearance. Through increasing fear of fat (FOF), PVD may be associated with cognitive restraint and compensatory behaviors. We utilized an adult sample (n = 247; 53.3% male sex assigned at birth) recruited through Amazon's MTurk prior to the COVID-19 pandemic to investigate associations between PVD, cognitive restraint and compensatory behaviors. Participants completed the Perceived Vulnerability to Disease Scale, Eating Disorder Diagnostic Scale, Dutch Eating Behaviors Questionnaire, and Goldfarb's Fear of Fat Scale. Mediation analyses were used to test our hypotheses. Perceived infectability (PVD-Infection) was associated with cognitive restraint and compensatory behaviors through increased FOF. Perceived germ aversion (PVD-Germ) was associated with cognitive restraint, but FOF did not mediate this association. Sex-stratified analyses revealed no significant sex differences. PVD may be an overlooked factor associated with cognitive restraint and compensatory behaviors in males and females. FOF was an important mediating factor in these associations. Increased engagement in cognitive restraint and compensatory behaviors may reflect attempts to reduce FOF. Future longitudinal research should explore whether PVD is a risk factor for cognitive restraint and compensatory behaviors.

Functional Connectivity within the Frontal–Striatal Network Differentiates Checkers from Washers of Obsessive-Compulsive Disorder

Background: Obsessive-compulsive disorder (OCD) is a psychiatric disorder with high clinical heterogeneity manifested by the presence of obsessions and/or compulsions. The classification of the symptom dimensional subtypes is helpful for further exploration of the pathophysiological mechanisms underlying the clinical heterogeneity of OCD. Washing and checking symptoms are the two major symptom subtypes in OCD, but the neural mechanisms of the different types of symptoms are not yet clearly understood. The purpose of this study was to compare regional and network functional alterations between washing and checking OCD based on resting-state functional magnetic resonance imaging (rs-fMRI). Methods: In total, 90 subjects were included, including 15 patients in the washing group, 30 patients in the checking group, and 45 healthy controls (HCs). Regional homogeneity (ReHo) was used to compare the differences in regional spontaneous neural activity among the three groups, and local indicators were analyzed by receiver operating characteristic (ROC) curves as imaging markers for the prediction of the clinical subtypes of OCD. Furthermore, differently activated local brain areas, as regions of interest (ROIs), were used to explore differences in altered brain functioning between washing and checking OCD symptoms based on a functional connectivity (FC) analysis. Results: Extensive abnormalities in spontaneous brain activity involving frontal, temporal, and occipital regions were observed in the patients compared to the HCs. The differences in local brain functioning between checking and washing OCD were mainly concentrated in the bilateral middle frontal gyrus, right supramarginal gyrus, right angular gyrus, and right inferior occipital gyrus. The ROC curve analysis revealed that the hyperactivation right middle frontal gyrus had a better discriminatory value for checking and washing OCD. Furthermore, the seed-based FC analysis revealed higher FC between the left medial superior frontal gyrus and right caudate nucleus compared to that in the healthy controls. Conclusions: These findings suggest that extensive local differences exist in intrinsic spontaneous activity among the checking group, washing group, and HCs. The neural basis of checking OCD may be related to dysfunction in the frontal–striatal network, which distinguishes OCD from washing OCD.

Perceived Vulnerability to Disease Questionnaire: psychometric validation with a Portuguese sample

Background

Individual differences in one’s perceived vulnerability to infectious diseases are implicated in psychological distress, social and behavioral disease avoidance phenomena. The Perceived Vulnerability to Disease Questionnaire (PVD) is the most extensively used measure when it comes to assessing subjective vulnerability to infectious diseases. However, this measure is not yet accessible to the Portuguese population. The present study aimed to adapt and validate the PVD with 136 Portuguese participants.

Methods

Factorial, convergent and discriminant validity (of both the scale and between each factor), and reliability analysis were assessed.

Results

A modified bifactorial model, comprised of Perceived Infectability and Germ Aversion factors, was obtained, with acceptable goodness-of-fit indices, adequate convergent and discriminant validity, and good internal consistencies.

Conclusions

Overall, the 10-items European-Portuguese PVD appears to be a reliable and valid measure of one’s perceived vulnerability to disease, with potential relevance for application in both research and clinical practice pertaining to disease-avoidance processes.