Obsessive-Compulsive Disorder 

Obsessive-Compulsive Disorder (OCD) is marked by the presence of obsessions and/or compulsions. Obsessions are recurrent and persistent thoughts, urges, or images that are experienced as intrusive and unwanted, whilst compulsions are repetitive behaviors or mental acts which a person feels compelled to perform in response to an obsession or in keeping with rules that must be enforced strictly.