Demographic information.

<p>uOCD = unmedicated OCD, mOCD = medicated OCD, uHC = unmedicated healthy controls, mPC = medicated patient controls. Group differences in age, years of education, Hamilton Anxiety Scale score (HAM-A), and Hamilton Depression Scale score (HAM-D) were evaluated with separate 2×2 ANOVAs using diagnosis (OCD, controls) and medication (unmedicated, medicated) as between-subjects factors. Chi-square tests compared gender (all groups), while independent samples t-tests were used to compare mOCD and uOCD groups on Yale-Brown Obsessive Compulsive Scale (Y-BOCS) scores. sd = standard deviation, D = main effect of diagnosis factor, M = main effect of medication factor, D×M = interaction between diagnosis and medication. Only those effects significant at p<.05 are shown, and followed up with post-hoc comparisons using independent-samples t-tests.