Absolute and relative volumesa of the insular cortex in obsessive–compulsive disorder and healthy controlsb.

OCD, obsessive–compulsive disorder.aCalculated as follows: (absolute insular volume/intracranial volume)×100.bAge and Beck Depression Inventory score were used as the covariates for both absolute and relative insular volumes. Intracranial volume was added as a covariate for absolute insular volume.cAge was used as a covariate.dOCD patients showed significantly larger anterior and smaller posterior insular cortical volumes than healthy controls (Analysis of covariance, P*P**P