[The ABC:s of obsessive-compulsive disorder].

Obsessive-compulsive disorder (OCD) affects approximately 1.3% of adults and is characterized by intrusive thoughts (obsessions) and repetitive behaviors (compulsions) aimed at alleviating distress. Despite its impact on daily functioning, OCD remains underdiagnosed. Models suggest that OCD arises from maladaptive learning processes and/or biological factors, such as genetic predispositions and dysfunctional abnormalities in the cortico-striato-thalamo-cortical loops. First line treatment for OCD in Sweden is exposure and response prevention (ERP), a form of cognitive behavioral therapy (CBT). Selective serotonin reuptake inhibitors (SSRI) are first line pharmacological treatment. If treatment response is inadequate, low-dose antipsychotics can be added, followed by a switch to clomipramine. Deep transcranial magnetic stimulation (dTMS) and deep brain stimulation (DBS) may be considered for severe, treatment-resistant OCD.