[When thoughts become compulsions. Obsessive-compulsive disorder in children].

OCD (obsessive-compulsive disorder) is characterised by the presence of annoying, unwelcome and intrusive obsessions and compulsions. The obsessions appear over and over and the child recognize them as something strange and unwelcome, but at the same time they are clearly a product of his/her own mind and not a hallucination or a thought disorder as seen in psychotic disturbances. Compulsions are imposed actions that the child feels it has to perform, often in a certain pattern. Both children and adults can suffer from OCD. Almost 2/3 of adults with OCD report onset of their OCD symptoms in childhood or early adolescence. Previously, OCD among children and adolescents was considered to be rare, but newer epidemiologic surveys show that 1-1% of children and adolescents suffer from OCD in such a degree that they fulfil the diagnostic criteria. The prevalence varies surprisingly little in various countries regardless of cultural background.