Cognitive triggers of auditory hallucinations: an experimental investigation.

It has proved difficult to establish the internal process by which mental events are transformed into auditory hallucinations. The earlier stages of the generation of hallucinations may prove more accessible to research. Cognitions have been reported by patients as a trigger of auditory hallucinations, but the role of these preceding thoughts has not been causally determined. Therefore, the role of cognition in triggering auditory hallucinations was tested in an experimental study. Thirty individuals who experienced auditory hallucinations in social situations entered a neutral social situation presented using virtual reality. Participants randomised to the experimental condition were instructed to think their hallucination-preceding thoughts, and those randomised to the control condition were instructed to think neutral thoughts. Twenty-seven participants (93%) were able to spontaneously identify a cognition which preceded a hallucination. There was no difference between the experimental and control groups in the occurrence or severity of auditory hallucinations in virtual reality. Virtual reality did not lead to physical side effects or an increase in anxiety. The relationship between antecedent cognitions and auditory hallucinations is likely to be more complex than the one tested. It is argued that the effect of cognition on auditory hallucinations may be mediated by affect but this needs to be investigated through further experimental research.