It is a chronic disease that progresses with obsessions and/or compulsions, significantly affecting the person's daily life, work or school success, family or social relationships. It often begins at a young age.

Obsessions are repetitive thoughts, urges or fantasies that are usually unintentional, contradict the person's views and beliefs, cause distress, and cannot be consciously dismissed. Obsessions about contamination, order, religious issues, sexuality, hoarding, harming or causing harm are common.

Compulsions are repetitive behaviors or mental actions that are mostly done to get rid of obsessive thoughts and to reduce the feeling of discomfort caused by the thought, but over time they themselves cause distress. Cleaning, washing, checking, counting, sorting, and organizing behaviors are also common compulsions.

When a person touches an object that they know is clean, they think their hand is dirty and feel the need to wash it, and they wash their hand over and over again because they think it is dirty even though they have washed it.

A combination of medication and psychotherapy is more effective in treatment.