Cognitive Inhibition in Compulsive Washing Disorder: IOR Paradigm

Inhibition of Return (IOR) as a cognitive inhibition function, refers to the relative suppression of orienting toward stimuli that had recently been considered. This function has an adaptive value in human beings (Wang and Klein, 2010). Regarding the core symptoms of Obsessive-Compulsive Disorder (OCD), deficit in cognitive inhibition is probable. However, results are inconsistent. Therefore, the present study aimed to study the probable IOR deficit in clinical sample with compulsive washing. This study was conducted with a comparative method. Beck Depression Inventory-version II (BDI-II), Obsessive- Compulsive Inventory-Revised (OCI-R), and emotional Inhibition of Return test were administered on 30 clinical samples with compulsive washing (20% male) and 30 normal samples (26/7% male). The results of multivariate analysis of covariance showed that there was no deficit in IOR in compulsive washing (F=1.256, P>.05; Wilk’s Lambda =. 866; Y2 = 0.134). On the other hand without considering group effect, there was a significant difference deference between reaction times in valid and invalid trails (t=2.29; P[.05) that shows the general inhibition of return phenomenon in the subjects. This research failed to show cognitive inhibition deficit in clinical samples of compulsive washing, however, the probability of inhibition deficit is suggested in other levels of inhibition such as behavioral one. Other theoretical and experimental implications have been discussed.