79. Association Between Illness Duration and Psychotropic Medication in Obsessive-Compulsive Disorder and Altered Brain Structural Covariance Networks: A Multi-Center Analysis

Abstract

Background: Brain's structural covariance network refers to the organized patterns of co-varying brain morphology that are thought to reflect trajectories of brain development and maturation. In particular, obsessive-compulsive disorder (OCD) is often diagnosed early in life, but the effect of illness duration and psychotropic medication on the brain structural covariance networks remains unknown. This study examined individualized brain structural covariance networks using graph theory. We compared individuals diagnosed with OCD to healthy controls (HC) and evaluated trends in relation to their duration of illness and medication status. Methods: T1-weighted brain magnetic resonance images acquired from 1,616 OCD patients and 1,463 HC across 37 datasets participating in the ENIGMA-OCD Working Group were analyzed; among these, twelve datasets were included for meta-analysis according to the medication status. Global network characteristics that measure the degree of network segregation (clustering coefficient and modularity), integration (global efficiency), and their balance (small-worldness) in addition to the degrees of inter-individual overlap for hub profiles (dice similarity coefficient) were calculated from individualized cortical-subcortical structural covariance networks. Results: Global network characteristics showed lower network segregation and small-worldness as well as decreased dice similarity coefficient in OCD compared to HC; medication status did not reveal significant influence on these global characteristics in OCD. Conclusions: Our findings of altered structural covariance patterns in relation to the longer illness duration for OCD may reflect increased connectedness of brain regions related to self-referential information processing, and isolation of brain areas relevant for insight, behavioral control, and visuospatial reasoning. Supported By: This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2017R1D1A1B03028464). ENIGMA is also supported, in part, by an NIH grant (U54 EB020403), and by public and private funding agencies worldwide. Keywords: Obsessive Compulsive Disorder (OCD), Structural Covariance, Graph Theory, Duration of Illness, Medications