Neurobiological aspects of obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a heterogeneous entity. One of the more important concepts to emerge in the past two decades of OCD research is the realization that the obvious clinical variability associated with the diagnosis likely reflects neurobiologically meaningful subtypes or dimensions of disease, in terms of pathophysiology. We review several pathophysiological models, emphasizing the ways in which disparate data may well reflect real differences among OCD subtypes. We present a brief heuristic model of OCD that is based on phenomenological characteristics, results of neuroimaging studies and informed by neuroanatomical considerations.