Dr Rodger's view of the clinical importance of the introduction of avatar therapy is encouraging. He makes a number of important points with which I entirely agree. In particular, the frail boundary between dissociation and psychosis was brought home to me by four adolescent girls in our trial, two of whom had been sexually abused in childhood, and experienced auditory, visual and somatosensory hallucinations. One girl re-experienced the rape every night and was convinced that the rapist entered her bedroom for that purpose.

In answer to Dr Rodger's question about the therapist's voicing of the avatar, it is a crucial requirement that the patient accepts the avatar as a realistic representation of their persecutory voice. This is achieved by asking the patient at first contact to report on the habitual phrases they hear. The therapist's voice is morphed into a variety of forms, from which the patient selects the one that is closest to the voice they hear. Patients assessed the closeness of the match at between 60 and 90%. In the first session of therapy the therapist, as the avatar, speaks the phrases the patient has reported hearing in order to establish the identity of the avatar as their persecutor. Of the 16 patients who experienced the full course of six sessions of therapy, only 2 failed to respond to the avatar as a convincing simulacrum of the voice they hear. Neither of them benefited from the therapy. We have discussed the possible mechanisms by which the therapy achieves its effects. ^{Reference Leff, Williams, Huckvale, Arbuthnot and Leff1}