[Neurobiology of obsessive-compulsive disorder]

Obsessive-compulsive disorder (OCD) is a psychiatric disorder characterized by unwanted and recurrent obsessions and compulsions. Several brain imaging studies report differences in either metabolism or blood flow between OCD patients and normal controls. The findings are obtained from the scans of patients after they performed a variety of tasks. The various kinds of tasks are set in relation to the research results. Furthermore, the article examines which changes are normalized after cognitive behavioural or medical treatment, and finally it summarises studies on to which extent it is possible to predict treatment outcome using neuroimaging.