[Neurobiology of obsessive-compulsive disorder]

In the last few decades, neurobiological research has considerably improved the understanding of the pathophysiological basis of obsessive-compulsive disorder (OCD), indirectly contributing to the improvement of diverse therapy strategies. A number of functional imaging studies have indicated functional deficits in frontostriatal networks, which can be subsumed in an orbitofrontal model of obsessive-compulsive disorder. A dysfunction is postulated in parallel frontostriatal circuits, leading to an imbalance in direct and indirect feedback loops and a disinhibition of thalamocortical activity. Neurochemical studies have shown that OCD is linked to changes of the central modulatory transmitter system, especially, the serotonin and dopamine system, which probably contribute to a direct and indirect dysregulation in various neural networks. Pharmacologically, the elucidation of these serotonergic and dopaminergic alterations and their interactions are of special interest.