[Encyclios]

The fear of contamination

One of the clinical samples in which a high propensity for disgust has been shown to be present is that of patients with obsessive-compulsive disorder, particularly with symptomatology of fear of contamination (Olatunji & Sawchuk, 2005). In fact, 50% of patients report that pathological behaviors toward hygiene are due to recurrent thoughts of contamination avoidance (Olatunji & Sawchuk, 2005). Furthermore, it has been hypothesized that the propensity for disgust itself may be one of the factors maintaining pathology (Olatunji & Sawchuk, 2005), if not even one of the factors increasing the incidence of patient drop-out (Ludvick, Boshen & Neuman, 2015).

Disgust is one of the six basic emotions (Ekman, 1993), with a precise physiological response, parasympathetic activity that produces increased salivation and nausea (De Jong et al., 2011), and a specific neural correlate, the insula (Sprengelmeyer, 2007).

It was initially studied as an aversion reaction towards certain foods, thus elicitating disgust, characterized both by physical appearance, and ideational character, which then report the knowledge of the origin of these foods (Rozin & Fallon, 1987; Rozin, Haidt, & McCauley, 2000). The behavioral response consists of distancing oneself from the disgusting object, as it could be harmful or contaminated, maintaining the body’s role of defense (Rozin & Fallon, 1987).

It can be divided into several domains, more sensory or culturally determined, depending on what kind of stimulus elicits them: central disgust, animal nature, interpersonal, and moral (Rozin, 2009). The last three are related to cognitive, rather than sensory, beliefs, and concern, respectively: contagion to mortality and decay, distance from those who are considered disgusting, and preservation of a social order (Rozin, 2009). With regard to Obsessive-Compulsive Disorder, research is more focused on the first domain, namely central disgust. It is characterized by

• rejection of oral intake;
• sense of dangerousness of the disgusting object;
• and potential contamination it may produce.

The primary role of central disgust is food rejection, so the mouth acquires the role of a gateway (Rozin & Fallon, 1987), and the belief that “one becomes what one eats” is reinforced (Rozin & Haidt, 2000). Given this premise, with regard to contamination, more related to touch and sight, Rozin proposes how two magical-sympathetic laws can regulate it: the law of contagion, once you are in contact with something contagious, you will always remain contaminated; and the law of similarity, two objects that appear the same in form, will also be the same in substance (Rozin & Fallon, 1987; Rozin & Haidt, 2000).

Do patients with Obsessive-Compulsive Disorder experience more disgust than others? How can the experience of disgust be measured in terms of individual differences? First, a distinction must be made between disgust propensity (PD), which is an individual’s ease of being disgusted, and disgust sensitivity (SD), which is the intensity of negative appraisal when experiencing disgust (Ludvick, Boshen & Neuman, 2015).

Work will be proposed that addresses disgust propensity in normal samples and those with Obsessive-Compulsive Disorder. For this purpose, in most studies, the instrument used is the Disgust Scale Revised (Olatunji et al., 2009), which assesses the inclination/propensity to feel disgust in multiple domains: animals, body products, death, violations of normal development, food, sex, hygiene, sympathetic laws (unlikely contagion). Although there has been interest in proposing new tools to better explain the variability of responses in patients with Obsessive-Compulsive Disorder (Melli et al., 2015a), the variability appears to be confounding to the conceptualization of the disorder, and consequently to subsequent treatment.