The Effect Of Childhood Trauma On Theory Of Mind In Obsessive-Compulsive Disorder

Background: Obsessive-compulsive disorder(OCD)is a psychiatric condition characterized by obsessions and compulsions.Previous studies have revealed social cognition deficits such as impairments in theory of mind(To M)in OCD,however,the results were not consistent.OCD is also often associated with adverse experiences such as Childhood trauma(CT)and CT is one of the strongest risk factors for OCD.The effect of CT on To M has been found in numerous psychiatric disorders but a direct relationship between CT and To M deficits in OCD has never been established.Therefore,the present study attempts to explore the effect of CT on To M in OCD.Methods: A number of 81 OCD patients(with CT=32,without CT=49)and 108 healthy controls(with CT=43,without CT=65)were included in this study.The Structured Clinical Interview for DSM-IV(SCID-IV)was used to diagnose the OCD cases and HCs,and the Childhood Trauma Questionnaire(CTQ)retrospectively assessed the level of CT among both groups.To M was evaluated with the Chinese version of the Yoni tasks.To M was assessed on four dimensions,namely first and second order affective and cognitive To M.Various neuropsychological assessments including the logical memory and visual reproduction tests,the information,arithmetic,similarity,and digit span subscales of Wechsler Adult Intelligence Scale(WAIS-RC),and the Letter-Number Span Test(LNST)were administered to the whole sample.The effect of CT on To M was assessed using the Analysis of Covariance(ANCOVAs).Pearson’s correlation analysis was performed between CT and its subtypes with To M dimensions.CT total and subtypes as predictive factors for To M were also analyzed using the hierarchical regression.Finally,the mediation and moderation analysis were performed to explore the relationship among CT,To M and OCD symptoms severity.Results:1.Significant group differences were found in education and memory scales,but age,gender and estimated intelligence quotient showed no group differences across the four groups.There was no significant difference between OCD＿CT and OCD＿No CT in the duration of disease.2.The ANCOVA analysis showed a statistically significant interaction of CT and OCD on both second order of affective and cognitive To M with p=0.03 and p=0.04 respectively,and no significant effect of CT or diagnosis alone was found across the four To M dimensions.Owing to the interaction effect of diagnosis and CT groups,a follow-up analysis of simple effect with Bonferroni adjusted was performed.It revealed a positive effect of CT < No CT in OCD(F = 6.98,p = 0.009)and effect of OCD < HC in CT(F = 6.50,p= 0.012)for affective second-order To M deficits.For cognitive second-order,the effect of CT>No CT in OCD(F =5.19,p = 0.024)and the effect of OCD>HC in CT were significant(F =5.64,p= 0.019).3.Correlation analyses showed a negative correlation between total CT and affective(r=-0.22,p=0.032)and cognitive(r=-0.21,p=0.037)second-order To M deficits in OCD respectively,and a negative correlation between emotional abuse(EA)and second-order affective To M(r=-0.25,p=0.015)and between sexual abuse(SA)and second-order cognitive To M(r=-0.21,p=0.037).In the HC group,second-order To M did not have any significant correlation.Within the OCD group,the hierarchical regression analysis revealed the predictive effect of EA on second-order affective To M deficits(p=0.028)and the predictive effect of SA on second-order cognitive To M deficits(p=0.040).The predictive factors of CT and its subtypes on To M deficits were not found in the HC group.4.The moderation analysis found a significant interaction effect of second order cognitive theory of mind on the relationship between childhood trauma and sexual abuse with OCD symptoms.The mediation analyses failed to reveal any significant mediation effects of To M deficits on the relationship between CT and OCD symptoms severity.Conclusions:1.CT has an effect on second order To M in OCD.Specifically,only OCD patients with CT showed deficits on second order affective and cognitive To M.2.Emotional abuse and sexual abuse have been found to be the most influential CT subtypes on second-order affective and cognitive To M deficits in OCD respectively.3.Second-order cognitive To M moderates the relationship between CT and OCD symptom severity.