As Professor Bordnick points out, imagination alone isn't a particularly powerful tool to recreate the situations in which a recovering addict learns to say 'no': 'As a therapist, I can tell you to pretend my office is a bar, and I can ask you to close your eyes and imagine the environment, but you'll know that it's not real'.
Rather than ask the patient to visualise a bar stocked with alcohol or a party where cigarettes are on offer, Bordnick uses a VR helmet along with other components such as olfactory stimulation and actor participation to create a highly plausible and immersive environment. Although the patient consciously knows he is taking part in a VR simulation, the immersion has proven sufficient to build intense cravings, just as if the focus of the addiction had really been present.
By supplying an enviroment that is realistic enough to stimulate cravings but remains controlled and safe, Bordnick can gradually train patients in the use of coping skills. As those skills will have been developed in the face of a close analogue of the real thing, the patient is much better equipped to contend with the challenge of the real-world situation.