The neuropsychology of adult obsessive-compulsive disorder: a meta-analysis.

A vast and heterogeneous body of literature on the neuropsychology of obsessive-compulsive disorder (OCD) has accumulated in recent decades, yielding inconsistent results. In an attempt to quantitatively summarize the literature, we conducted a meta-analysis of 115 studies (including 3452 patients), comparing adult OCD patients with healthy controls on tests of 10 neuropsychological domains. Across studies, medium mean effect sizes were found for all executive function subdomains, processing speed, and sustained attention. Small effect sizes were found for visuospatial abilities and working memory. A large effect size was found for non-verbal memory whereas a small effect size was found for verbal memory, where only the former was found to be associated with impairments in executive functions. Moderators of effect sizes were also investigated. Results are discussed in terms of their clinical significance as well as their implications for current neurobiological models of OCD and methodological caveats.