Let's get dirty!
To begin with, just a small clarification that we are not being sleazy. The title is just a poor attempt at humour. Exposure response prevention therapy (ERP) is a kind of Cognitive Behavioural Treatment (CBT) that is largely used in the treatment of OCD. This therapy uses the concept of habituation in order to treat OCD. Habituation is a form of non-associative learning in which an innate response to a stimulus decreases after repeated or prolonged presentations of that stimulus. This is one of the reasons why ERP works. If someone is scared of dirt and you make them touch a dirty shoe repeatedly. The anxiety they get the second time is less than the first time because the mind is already aware of what is going to happen. Continuous exposure to anxiety inducing situations will in the end reduce the anxiety induced by the environment. Another thought behaviour that guides the practice of ERP is emotional processing theory. How you process and react to something changes overtime. A certain behaviour is something you cultivate and inhibit. In OCD the patient is plagued with intrusive thoughts this acts as a response. As a reply to this one has a compulsive action or response. ERP is a way of preventing your body from responding in the way that it normally would. For example, there is a ‘Harry’ who is obsessed about Voldemort. His obsessions result in him having extreme anxiety and spurting spells at random things. Now in Exposure Response Prevention therapy he-who-must-not-be-named is named and they try to train and control Harry's reactions. The more he is exposed to the name the lesser anxiety it generates in him. This therapy is used to treat even other kinds of anxieties. The therapy proved to be effective because using it one can handle and give attention to the individual anxieties a person has. This therapy proves to be more effective than medication alone as it has a prolonged effect on the body. The response prevention is internalised by the patient and that way the person is more equipped to handle situations better. ERP tries to reduce the importance certain obsessions attached to your brain. It reduces the demon into what it actually is, just another bad thought.