Perception bias of disgust in ambiguous facial expressions in obsessive–compulsive disorder Kyungun Jhung a , Kee Namkoong a , Jee In Kang a,b , Ra Yeon Ha a , Suk Kyoon An a , Chan-Hyung Kim a , Se Joo Kim a, ⁎ a Department of Psychiatry and Institute of Behavioral Science in Medicine, Yonsei University, College of Medicine, 250 Seongsan-no, Seodamun-gu, Seoul, South Korea b Department of Psychiatry, Ilsan Hospital, National Health Insurance Corporation, Goyang, Gyeonggi-do, South Korea abstract article info Article history: Received 8 December 2008 Received in revised form 20 November 2009 Accepted 21 November 2009 Keywords: Disgust Facial expressions Ambiguous stimuli OCD Symptom dimensions Disgust Scale Impaired recognition of facial expressions of disgust has been suggested for patients with obsessive– compulsive disorder (OCD). This study aimed to compare the perception of negative emotions by OCD patients and controls using both non-ambiguous and ambiguous facial expressions. Forty-one OCD patients and thirty- seven controls performed the computerised emotion perception task. There were no differences between OCD patients and controls in the frequency of correct identification of non-ambiguous facial expressions. However, OCD patients were more likely to perceive disgust and less likely to perceive anger in response to ambiguous facial expressions when controlling for covariates. In OCD patients, a higher cleaning dimension was associated with a lower perception of anger and a higher perception of disgust when presented with ambiguous facial expressions. The domains of core disgust and contamination-based disgust domains of disgust sensitivity were positively correlated with the perception of ambiguous facial expressions as disgust, as well as cleaning symptom dimension scores. Our findings suggest that OCD patients, particularly those with higher washing/ contamination symptoms, are more likely to perceive disgust in ambiguous facial expressions. © 2009 Elsevier Ireland Ltd. All rights reserved. 1. Introduction Disgust is thought to underlie various psychiatric illnesses. Initially defined as a revulsion response to distasteful foods (Darwin and Ekman, 1998), the current concept of disgust now also includes responses to a wide range of stimuli, such as poor hygiene, potential for disease and violations of the normal body envelope (Rozin and Fallon, 1987). At its core, disgust functions to prevent contamination and disease (Darwin and Ekman, 1998) by the characteristic behavioural dimen- sion of avoidance (Rozin and Fallon, 1987). Disgust also has specific physiological manifestations, such as nausea and a distinct facial expression of narrowed nostrils, wrinkling of the brow and raising of the upper lip (Phillips et al., 1998; Rozin et al., 1994). From a developmental perspective, perception of disgust is thought to be absent at birth and to develop during childhood (Rozin and Fallon, 1987). The learning process is thought to occur through experience with other peoples' disgust, and to involve the identification of disgust-eliciting stimuli, the recognition of other peoples' facial expressions of disgust, and the correlation between the two (Sprengelmeyer et al., 1996). If there is a dysfunction in this appraisal process, the stimuli that elicit disgust in those with a dysfunction may be dissimilar from the stimuli that elicit disgust in others (Sprengel- meyer et al., 1996). Impairment in this disgust appraisal process has been suggested to be closely related to obsessive–compulsive disorder (OCD). OCD is a relatively common disorder, characterised by persistent and unwant- ed thoughts and ritualistic behaviour. Among the heterogeneous symptoms of OCD, concerns with contamination are commonly involved. OCD patients often exhibit heightened appraisals of vulnerability to infection and spread of contamination in response to offensive objects, which elicit washing compulsions (Olatunji and McKay, 2007). Because the situations in which OCD patients experience disgust are different from those in which normal individuals experience disgust, it has been hypothesised that the learned association between the emotion of disgust and the facial expressions of disgust may have failed to develop (Sprengelmeyer et al., 1997). Experimental support for this theory of disgust perception in OCD, however, has been mixed. Sprengelmeyer et al. (1997) reported that all OCD patients examined showed a distinct and significant impairment in recognising facial expressions of disgust. However, subsequent studies have not revealed a clear association between OCD and the failure to recognise facial expressions of disgust. Parker et al. (2004) and Buhlmann et al. (2004) both reported no significant differences between OCD patients and normal controls with respect to facial expression recognition. In a more recent study, the results of Sprengelmeyer et al. (1997) were replicated, but the magnitude of the Psychiatry Research 178 (2010) 126–131 ⁎ Corresponding author. Tel.: +82 2 2228 1620; fax: +82 2 313 0891. E-mail address: kimsejoo@yuhs.ac (S.J. Kim). 0165-1781/$ – see front matter © 2009 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.psychres.2009.11.023 Contents lists available at ScienceDirect Psychiatry Research journal homepage: www.elsevier.com/locate/psychres