Introduction

Obsessive-compulsive disorder (OCD) is a common neuropsychiatric condition, affecting 1-2% of the population globally. Despite considerable heterogeneity in the precise symptoms experienced across different patients (e.g., some patients are preoccupied with worries of contamination, whereas others obsess about symmetry), there is growing realization that common neurobiological processes may contribute to vulnerability towards OCD and its persistence. OCD is regarded as the archetypal disorder of compulsivity (i.e. a tendency towards repetitive habitual actions that a person feels a need to perform, with these tendencies having untoward functional consequences, such as detracting from overall life goals, or quality of life). Although the optimal definition of compulsivity likely depends upon perspective and context1, within this broad clinical framework, disorders of compulsivity include OCD and related disorders such as hoarding disorder, body dysmorphic disorder, trichotillomania, skin picking disorder, and Tourette’s2. Here we focus on recent advances in understanding the neurobiology of OCD, and the clinical implications of such knowledge viewed in the context of prevailing disease models.