Obsessive Compulsive Disorder – People with obsessive-compulsive disorder (OCD) experience obsessions, compulsions or both. Obsessions are unwanted and disturbing thoughts, images or impulses that suddenly pop into the mind and cause a great deal of anxiety or distress. Compulsions are deliberate behaviours (ie. washing, checking, ordering) or mental acts (ie. praying, counting, repeating phrases) that are carried out to reduce the anxiety caused by the obsessions.