Disgust Responding In Obsessive-Compulsive Disorder With Or Without Contamination Washing Symptoms:An ERP Study

Objective: Obsessive-compulsive disorder(OCD)is clinically heterogeneous.Different obsessions and compulsions have been related to different machenism,neuropsychological profiles,and treatment responses.Growing evidence have suggusted that disgust played an important role on the etiology and maintenance of obsessive-compulsive disorder with contamination/washing symptoms.The disgust reaction could not only be elicited by feces and rotten food,namely core disgust,but also be elicited by immoral behavior,namely moral disgust.However the connection between disgust and other obsessions and compulsions is unclear.The curent paper aim to explore differential disgust respongding of obsessive-compulsive disorder with or without contamination/washing symptoms via the event-related potencial(ERP)technique,adding more evidence for the heterogeneity of OCD.Methods:Totally 57 patients diagnosed with obsessive-compulsive disorder(OCD)and50 age-,gender-,level of education-matched healthy control(HC)were recruited for the study.Patients with OCD were devided into two groups,namely contamination washing symptoms group(WG)and other symptoms group(OG)based on the contamination washing symptoms.All participants were assessed with Padua inventory-Washington State University revision(PI-WSUR),Yale-Brown Obsessive-Compulsive Scale(Y-BOCS),Hamilton anxiety scale(HAMA)and Hamilton depression scale(HAMD),and ERP data were recorded during lexical decision task.Results:(1)Behavior results of lexical decision task: OG performanced low accuracy on physical disgust words and mora disgust words than WG and HC(P<0.05).There was no difference on neutral words(Ps>0.05).WG and OG both showed longer reaction time to two kind of disgust words than HC(Ps<0.05).Finally,compared with HC,WG and OG also evaluated high level of disgust to disgust words(Ps < 0.05).But no significant difference exsited in neutral words(Ps>0.05)between three groups.(2)ERP results:WG elicited significantly larger P2 amplitude to neutral words than HC(Ps<0.05).There was no difference responding to disgust words between groups(Ps>0.05).N2 amplitudes induced by physical disgust words in WG were larger than OG and HC(Ps<0.05).And compared to OG and HC,WG elicited significantly larger N2 amplitude to moral disgust words and neutral words(Ps<0.05),no difference was found betweent OG and HC.Finally,WG elicited larger LPC amplitudes than OG(Ps <0.05).Core disgust words elicited larger LPC amplitudes than moral disgust words,and the two former were both lager than neutral words.Pearson correlation analysis showed that contamnination washing factor scores was significantly associated with P2amplitudes(Ps<0.05)induced by disgust words,no significant association was found between other symptoms factors scores and ERP data.Conclusion: OCD patients with or without contamination washing symptoms tend to report intense disgust feelings.OCD patients with contamination washing symptoms performance differently on the process of disgust,including contamination belief,attention bias of contamination,compared with OCD patients without contamination washing symptoms,so electroencephalogram under disgust stimuli could be potential criterion to distinguish OCD patients with different symptoms.The present study adding more Electrophysiological evidence for the heterogeneity and clinical treatment of OCD.