Obsessive-compulsive disorder (OCD) is characterized by persistent, recurring thoughts, images, or impulses and repetitive behaviors or mental acts that individuals are compelled to perform in order to reduce anxiety caused by obsessions. Obsessions and compulsions can be time consuming and intrusive, affecting functioning and causing distress. Symptoms of OCD can present in various domains, such as harm, contamination/cleaning, sexual behavior, symmetry/exactness, religiosity, hoarding, somatic, checking, repeating, counting, and miscellaneous. Individuals can experience distress related to multiple domains simultaneously. OCD can worsen over time as avoidance of feared stimuli can lead to increased anxiety, impaired functioning, and social isolation. Researchers have identified factors thought to maintain OCD symptoms, such as need for certainty, difficulty with change, and distress tolerance issues. Effective treatments for OCD include selective serotonin reuptake inhibitors and exposure and response prevention, which involves exposing individuals to feared objects, thoughts, or situations while preventing compulsive behaviors and is considered the gold standard OCD treatment.