212. Inducing Hallucinations in Participants From the General Population: The Role of Negative Emotions and Cognitive Resources

Abstract

Background: Hallucinations are a main symptom of psychotic disorder but are also prevalent in 6% of the general population (Linscott & van Os, 2013). However, the cognitive and emotional mechanisms underpinning hallucinations are still poorly understood. The aim of the present study was to explore the specifc role played by negative emotions and cognitive resources in the triggering of hallucinations in a healthy sample. Methods: A two‐by‐two factorial design was used to examine the effect of emotions (Neutral vs. Negative) and of available cognitive resources (High vs Low) on hallucinations. The preliminary sample was composed of 160 healthy participants aged between 18 and 30 years old who were randomly assigned to one of the four conditions Negative emotions were induced in two ways: (1) testing room lighting (darkened) and (2) pictures from the International Affective Picture System. Cognitive resources were manipulated using a visual N‐Back task (0‐Back or 1‐Back). During the N‐Back task, participants were also required to listen to recordings of white noise (i.e., a heterogeneous mixture of sound waves extending over a wide frequency range such as the noise heard from a radio when it is not tuned to a station). Participants had to report if they heard any signifcant word or sound embedded in the white noise. Finally, participants were asked to complete a questionnaire assessing hallucination proneness. Results: Analyses (factorial ANOVA) revealed signifcant interaction effects between emotions (neutral vs. negative) and cognitive resources (high vs. low) on the number of sounds heard in the white noise, the clarity of the sounds and the associated certitude. In addition, the number of sounds heard in the white noise as well as the associated certitude and clarity were signifcantly correlated with the tendency to hear voices in everyday life. Conclusion: For the frst time in the literature, the present study provided evidence for an interaction effect in hallucinations triggering between nega‐tive emotions and cognitive resources. In particular, participants with low cognitive resources and in a negative emotional state tended to hear more sounds, to be more convinced of having heard something, and to perceive the sounds with a greater clarity. Such results are in agreement with the cognitive model of hallucination pro‐posed by Waters et al. (2012) and provide new data for the understanding of the emotional and cognitive mechanisms underpinning hallucinations. Linscott RJ, van Os J., 2013. An updated and conservative systematic review and meta‐analysis of epidemiological evidence on psychotic experiences in children and adults: on the pathway from proneness to persis‐tence to dimensional expression across mental disorders. Psychol Med 43, 1133‐1149. Waters F, al., 2012. Auditory hallucinations in schizophrenia and non‐schizophrenia populations: a review and integrated model of cognitive mechanisms. Schizophr Bull 38, 683‐693.