A comparison of executive function in Body Dysmorphic Disorder (BDD) and Obsessive-Compulsive Disorder (OCD)

Evidence now suggests executive dysfunction in Body Dysmorphic Disorder (BDD) which may be related to Obsessive-Compulsive Disorder (OCD). However, neurocognitive performance in the two disorders has rarely been compared. This study compared 14 BDD participants on neurocognitive tasks taken from the Cambridge Automated Neuropsychological Test Automated Battery (CANTAB) with previously published data from 23 OCD participants (Purcell, Maruff, Kyrios, & Pantelis, 1998). Effect sizes from three executive function tests (Spatial Span, Spatial Working Memory and Stockings of Cambridge), and one visual memory task (Pattern Recognition) were compared for group differences using difference and equivalence testing. Equivalence testing was used to determine whether BDD and OCD effects sizes were equivalent, non-equivalent or equivocal. Results indicated an equivocal pattern for Spatial Span, Spatial Working Memory, Pattern Recognition and most Stockings of Cambridge measures. However, results for Stockings of Cambridge accuracy measure indicated a non-equivalent pattern, with BDD but not OCD participants performing significantly worse than controls. Results suggest a number of similarities in neurocognitive function in BDD and OCD, although it was not possible to establish statistical equivalence on most study measures. The findings raise the possibility of more severe planning deficits in BDD compared to OCD.