[Diagnosis and treatment of obsessive compulsive disorder].

Obsessive-compulsive disorders (OCD) are common and often chronic mental illnesses, characterized by recurring, intrusive thoughts, ideas and impulses (obsessions) and repetitive, stereotypical behaviors (compulsions). Etiopathogenetically, OCD is explained by a complex interplay of genetics and epigenetics, neurotransmission, imbalances in cortico-striato-thalamo-cortical circuits, as well as learning mechanism and environmental factors. In ICD-11, OCD is now classified in the chapter "Obsessive-compulsive and related disorders", which share compulsive and impulsive behavioral patterns. This article provides diagnostic recommendations, common psychiatric comorbidities, and key differential diagnoses. In terms of psychotherapy, disorder-specific cognitive behavioral therapy (CBT) with exposure and response prevention is highly effective and recommended as first-line treatment. New approaches describe intensified and internet-based formats as well as modern developments in CBT. Pharmacologically, serotonin inhibitors (SSRIs and Clomipramin) are recommended at high dosages. Atypical antipsychotics may be used in low dosages for augmentation. For treatment-resistant cases, brain stimulation techniques such as repetitive transcranial magnetic stimulation and bilateral deep brain stimulation may be considered following a careful risk-benefit analysis.