The current status of mental contamination in obsessive compulsive disorder: A systematic review.

BACKGROUND AND OBJECTIVES: Over the past 25 years Mental Contamination (MC) has become recognised as a distinct construct, particularly in relation to Obsessive Compulsive Disorder (OCD). MC is defined as feelings of contamination, often located internally, that arise in the absence of contact with a contaminant, with the source proposed to be human. Despite considerable interest from researchers and clinicians, there has not been a systematic review on the relationship between MC and OCD. Therefore, a systematic review was conducted to summarise and synthesise the current status of phenomenological and experimental evidence, mechanisms, assessment, measurement, and treatment of MC in OCD (PROSPERO: CRD42021223119). METHODS: All study designs were eligible provided the focus of the study was on MC and the implications of the study were linked to OCD. We searched PsychINFO, Embase, Medline, Ethos, ProQuest, conference abstracts and trial registries between 1990 and 2021. The Mixed Methods Appraisal tool was used to assess methodological quality of included studies. RESULTS: We found 58 reports with a total of 67 studies that met criteria for inclusion in the review. Twenty-three of these studies used clinical samples, 28 were experimental, 12 focused on phenomenology and 8 addressed treatment. The quality of the studies was variable. LIMITATIONS: Grey literature was not included, thus there may be further unpublished MC studies that have not been included in the review. CONCLUSIONS: Based on the findings, mental contamination is a robust clinical construct within OCD that has important implications for understanding and treating the disorder.

Sensitivity to being betrayed and betraying others in obsessive compulsive disorder and depression.

OBJECTIVES: Mental contamination (MC) describes subjective internal feelings of 'dirtiness', which are experienced in the absence of direct physical contact/contaminants. There is evidence of a link between MC in obsessive compulsive disorder (OCD) and the experience of past betrayals. However, it has also been noted that 'perpetrators' also experience MC. We aimed to replicate the previous finding of specificity of OCD for sensitivity to being betrayed by comparing with those suffering from depression, and to extend this by evaluating whether people with high MC OCD are also relatively more sensitive to the idea that they might betray others compared to those with low levels of MC OCD. DESIGN: A cross-sectional, between-groups design was used. METHOD: Four groups, high MC OCD (N = 60), low MC OCD (N = 61), depression (N = 28), and non-clinical controls (N = 46) completed online questionnaires. Participants were recruited through the National Health Service (NHS) and social media. RESULTS: Relative to all groups, the high MC OCD group had significantly higher scores both for betrayal sensitivity and sensitivity to betraying others. The depression group showed similar levels to low MC OCD in betrayal sensitivity but were significantly lower (and comparable to non-clinical controls) in sensitivity to betraying others. CONCLUSIONS: Betrayal sensitivity occurs trans-diagnostically. There may be a specific link between the development of OCD and the perception of betraying others, perhaps linked to the trauma of being betrayed making those so affected more likely to worry about their own responsibility for betraying others. PRACTITIONER POINTS: Clinicians should, across diagnoses, attend to sensitivity to being betrayed and the experiences which may have led to this. Current treatments for MC OCD recommend working with historical experiences of 'betrayal'. This study suggests that people with OCD also have an increased sensitivity to the idea of being a 'perpetrator' of betrayal linked to high responsibility beliefs. Specifically for OCD, it is possible that the experience of previously being betrayed results in increased current sensitivity to being responsible for being a 'betrayer'. It may, therefore, also be useful for therapists to consider if patients with MC OCD are concerned about potentially betraying others and to consider this within the formulation. The focus of clinical work could be to redefine these difficulties by reappraising beliefs regarding experience of betrayal and the likelihood of betraying others. Elevated levels of betrayal sensitivity were found in people with depression, and this may need to be considered in treatment approaches.