Mental contamination in obsessive–compulsive disorder

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Abstract

It was recently proposed that feelings of contamination can arise in the absence of physical contact with a contaminant. Currently, there are limited data regarding this construct of ‘mental contamination’ although it is hypothesised to be relevant to obsessive–compulsive disorder (OCD) where compulsive washing in response to contamination fear is a common presentation (Rachman, 2006). This research examined the presence of mental contamination in OCD. Participants (N=177) with obsessive–compulsive symptoms completed questionnaires to assess mental contamination, OCD symptoms and thought-action fusion (TAF). Findings indicated that 46% of participants experienced mental contamination, and severity was associated with severity of OCD symptoms and TAF. Mental contamination in the absence of contact contamination was reported by 10.2% of participants. Similar findings were reported in a sub-sample of participants who had received a formal diagnosis of OCD (N=54). These findings suggest that mental contamination is a distinct construct that overlaps with, but is separate from, contact contamination, and provide preliminary empirical support for the construct.

Highlights

► We examined mental contamination in people with OCD symptoms. ► Fourty-six percent experienced feeling dirty in the absence of physical contact with a contaminant. ► Mental contamination was associated with OCD symptoms and thought-action fusion. ► Mental contamination overlapped with, but was distinct from, contact contamination.

Introduction

Rachman, 2004, Rachman, 2006 theory of the fear of contamination postulates that feelings of dirtiness and contamination can arise following physical contact with a contaminant (contact contamination) but also in the absence of contact with a physical pollutant (mental contamination). Mental contamination is thought to occur in a number of forms and is associated with emotional and/or physical violations, such as degradation, betrayal, abuse. Mental contamination can also arise after experiencing repugnant unwanted intrusive thoughts, memories and mental images. According to the theory, contact and mental contamination regularly co-occur, but the relationship is asymmetric; many people with mental contamination report symptoms of contact contamination, but few people with contact contamination present with accompanying mental contamination (Rachman, 2006). Their co-occurrence is likely due to the fact that mental and contact contamination share a number of overlapping features, such as feelings of discomfort and dread, and the resulting urges to wash, clean and avoid re-contamination.

Mental contamination is relevant to a number of psychological disorders including obsessive–compulsive disorder (OCD), post-traumatic stress disorder (PTSD) and specific phobia. It is conceptually related to PTSD due to its association with physical violation, and to specific phobia due to the similarities in emotional and behavioural reactions (e.g., strong feelings of disgust) evoked by contamination fear and other phobias (e.g., Rachman and Hodgson, 1980, Rachman, 2006). Mental contamination generates strong urges to wash in order to remove the feelings of dirtiness and pollution, and hence has particular relevance to OCD, in which compulsive cleaning driven by a fear of contamination is reported by around 38% of patients (Calamari et al., 2004, Foa et al., 1995). Mental contamination is also hypothesised to be related to checking compulsions and repetitive reassurance seeking.

To date, the evidence for the presence of mental contamination in anxiety disorders is based on case studies of patients with OCD and/or PTSD. These clinical observations indicate that feelings of dirtiness, contamination and pollution can arise in the absence of physical contact with a contaminant (e.g., de Silva and Marks, 1999, Eysenck and Rachman, 1965, Gershuny et al., 2003, Rachman, 2006, Volz and Heyman, 2007). Furthermore, preliminary findings suggest that mental contamination may be present in a proportion of PTSD sufferers, especially when the trauma involves a physical violation. For example, Fairbrother and Rachman (2004) reported that 20 out of 50 female victims of sexual assault demonstrated significant levels of mental contamination. Almost 2/3rds of the sample reported feeling morally tainted, internally dirty and polluted, and these feelings could be re-evoked by recalling memories and mental images of the assault. These feelings of mental contamination triggered excessive washing that was reported to be ineffective. Just over half (51%) had a long or hot shower, 9% carried out extra washing of genitals and 6% used special cleaning products, but 34% of the sample still felt contaminated even after washing. Case studies can be persuasive, but systematic investigations of the presence of mental contamination are needed in order to verify the phenomenon.

Many researchers view OCD and other anxiety disorders on a continuum and symptoms similar to those reported by clinical populations found in healthy populations (Olatunji, Williams, Haslam, Abramowitz, & Tolin, 2008). Indeed, the cognitive approach to OCD is predicated on unwanted intrusive thoughts being a normal phenomenon (Rachman, 2003, Salkovskis, 1985). Despite some controversy (Rassin et al., 2007, Rassin and Muris, 2007), it is reasonable to consider that mental and contact contamination fears, like other forms of anxiety, have multiple dimensions (Abramowitz et al., 2010) and are on a continuum; this indicates that mental contamination can be studied in non-clinical populations. Psychometric analyses of contamination fear within healthy populations have shown that mental contamination is related to OCD symptomatology and to thought-action fusion (TAF) a cognitive bias commonly seen in OCD (Shafran, Thordarson, & Rachman, 1996). TAF is ‘the belief that thinking about an unacceptable or disturbing event makes it more likely to happen, and the belief that having an unacceptable thought is the moral equivalent of carrying out the unacceptable or disturbing action’ (Shafran et al., 1996, p. 379). TAF is thought to contribute to the maintenance of mental contamination by raising estimations of the probability and severity of potential harm, increasing feelings of harm, guilt and responsibility, and contributing to the inference that danger and contamination is present (Rachman, 2006).

Using self-report measures, Cougle, Lee, Horowitz, Wolitzky-Taylor, & Telch (2008) found that a measure of mental contamination was significantly positively associated with symptoms of OCD in healthy students, even when depressive symptoms and levels of guilt were controlled for. Similar findings have been reported using the mental contamination subscale of the Vancouver Obsessive Compulsive Inventory (VOCI; Thordarson et al., 2004, Rachman, 2006). Radomsky et al. (submitted) found that in a sample of 142 students, scores on the mental contamination subscale of the VOCI were highly correlated with contamination sensitivity, TAF, contamination specific TAF, anxiety and disgust, even when depression was controlled for. Taken together, these findings suggest that mental contamination is related to OCD symptoms and to TAF in healthy populations.

Fears of contact and mental contamination are conceptually and empirically differentiated on some self-report measures of OCD symptoms in non-clinical samples (Rachman, 2006). In addition, experimental work in healthy samples has indicated that there is a relationship between physical and moral purity. For example, Zhong and Liljenquist (2006) found that when healthy participants were asked to recall unethical memories or copy out immoral stories, they were more likely to complete word fragments to form washing related words, more likely to rate cleaning products as more desirable than general household objects and chose antibacterial handwipes over pencils when offered a choice of free gift. Similarly, Schnall, Benton, and Harvey (2008) demonstrated that physical cleaning reduced the severity of participants’ negative moral judgments. Furthermore, experimental work has indicated that it is possible to evoke feelings of mental contamination and washing behaviours in healthy students by asking them to image either receiving or perpetrating a non-consensual kiss (Fairbrother et al., 2005, Herba and Rachman, 2007, Radomsky and Elliot, 2009, Rachman et al., 2012). Research has shown that imagining a consensual kiss with a man described as immoral was enough to evoke feelings of mental contamination in health participants (Elliot & Radomsky, 2009) and that appraisal variables uniquely predict feelings of mental contamination (Radomsky & Elliot, 2009).

If mental contamination is a clinically relevant phenomenon in its own right, separate from contact contamination and general negative affect, then its presence may require a different treatment intervention (Jacobi et al., 2005, Rachman, 2006). However, at present there are limited data pertaining to the presence of mental contamination in clinical populations. Therefore, the aim of the studies reported here were to investigate the presence of mental contamination in people with significant obsessive–compulsive problems and establish whether it is distinct from contact contamination and general negative affect. Study 1 was a preliminary study that explored these relationships in a large sample of people with high obsessive–compulsive (OC) symptoms. These relationships are then examined in more detail in a sub-sample of participants with a formal diagnosis of OCD in Study 2.

Section snippets

Aims & hypotheses

The primary aim of this study was to establish the proportion of people with OC symptoms who experience mental contamination, using a measure of mental contamination (VOCI-MC; Rachman, 2006, see Study 2 for details). In order to receive a formal diagnosis of OCD, a patient must be diagnosed by a mental health professional using a structured interview such as the Anxiety Disorders Interview Schedule for DSM-IV (ADIS-IV; Brown, DiNardo, & Barlow, 1994). All participants reported that they had

Study 2

As far as is known, Study 1 is the first to systematically investigate the nature of mental contamination in OCD by studying a large sample of people with high OC symptoms, recruited from a number of diverse sources. Most importantly, it provides an estimate of the number of people with high OC symptoms for whom mental contamination is likely to be a clinically relevant feature (46.3%). However, a major limitation of Study 1 was the lack of formal diagnoses of patients’ symptoms as the

General discussion

The results indicate that mental contamination is more common than previously thought in people with obsessive compulsive disorders, and adds to the growing body of evidence for the existence of the phenomenon (e.g., Cougle et al., 2008, Rachman, 2006, Radomsky et al.,). In Study 1, 46.3% of people with high OC symptoms reported mental contamination fear, suggesting that they had some experience of contamination in the absence of physical contact. Similarly, the findings of Study 2 indicated

Acknowledgements

This research was supported by a University of Reading Pump PrimingFund awarded to Professor Roz Shafran and Simon Enright. The work reported here formed part of a Ph.D. dissertation submitted to the University of Reading, May 2010. The authors are indebted to Simon Enright and Berkshire Healthcare Foundation NHS Trust for their support in this research, and are grateful to Louise Onslow for her assistance in recruiting participants.

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