Morphologic Features of the Amygdala and Hippocampus in Children and Adults With Tourette Syndrome

Abstract

Tourette syndrome (TS) is defined by the presence of motor and phonic tics that begin in childhood and that fluctuate in severity across time. Obsessive-compulsive disorder (OCD) and attention-deficit/hyperactivity disorder (ADHD) are commonly co-occurring conditions. Pediatric-onset OCD and TS, and possibly some forms of ADHD, are thought to represent alternative manifestations of an underlying set of vulnerability genes that predispose to semicompulsory behaviors.¹ These genes are thought to produce anatomical and functional disturbances in corticostriatothalamocortical circuits.^2,3 The basal ganglia are an important component of these circuits and are thought to be involved centrally in the generation of tics and other compulsory behaviors. One of these circuits projects to and from limbic regions and associated anterior cingulate cortices.⁴ Although no published studies thus far have assessed the morphologic features of the limbic portions of these circuits in persons with TS, considerable circumstantial evidence suggests that limbic structures are involved in the pathogenesis of TS.