Although hearing voices is one of the main symptoms of psychosis there are thought to be many more people who hear voices than who suffer from psychosis. This is particularly true of children and adolescents and the great majority of children who hear voices do not go on to develop psychosis. Researchers from the University of Groningen in the Netherlands looked into the auditory vocal hallucinations of 3,870 seven and eight-year-olds. They found that over the course of the year 9% of the children heard voices. 15% of the children who heard voices suffered psychological distress and/or had problem behaviour. More children heard voices in rural areas but the consequences of doing so were more severe in urban ones. There was no link between the level of the children's development and their propensity to hear voices.
Bartels-Velthuis, Agna A. ... [et al] - Prevalence and correlates of auditory vocal hallucinations in middle childhood British Journal of Psychiatry January 2010, 196(1), 41-46