In Vivo Desensitisation is a form of treatment in which the patient experiences the problem area in real life in the presence of the therapist. For example in the case of a patient who has difficulty going into department stores, the therapist would gradually introduce him/her to entering the department store and remaining in the store for increasing periods of time. As the patient progresses and becomes more familiar with the store he/she will be able to venture deeper into the building and further away from the exit. As confidence builds they become relaxed enough to make purchases, ask assistants for advice, wait to be served at the check out and use the lifts and escalators. All this takes place within the context of the treatment session and the therapist is present through out, offering encouragement and giving emotional support.
A similar approach can be employed for people who have difficulties travelling on various forms of public transport, and is an especially helpful form of treatment for people who are phobic about travelling on underground trains.
While the treatment of agoraphobic patients requires increasing the distance travelled from base, some in vivo desensitisation can take place in the consulting room, such as the treatment of spider phobia and wasp phobia. With larger animals the early stages of the treatment begin in the consulting room using photographs and books and then when the patient is comfortable with these moves to encounter these animals in the environment.
An example of this is snake phobia where the patient starts the treatment by looking at pictures of snakes, then looking at toy snakes and eventually handling toy snakes of increasing size. When this has been achieved the therapist then accompanies the patient to the Reptile House to view live snakes.
At all stages of the treatment great care needs to be taken to ensure that the patient does not experience excessive anxiety, as this is counterproductive. The treatment is carefully graded so that each successful stage promotes greater achievements. A well-managed progression should lead to ultimate recovery from the phobia, this is particularly true in the case of well-motivated patients.