Hallucinations in children and teenagers admitted to Bethlem Royal Hospital in the nineteenth century and their possible relevance to the incidence of schizophrenia.

The case notes of 1069 children and teenagers admitted to Bethlem Royal Hospital, ("Bedlam"), in the nineteenth century were analysed with particular reference to the frequencies and types of hallucinations. There was a significant increase (P less than 0.001) in the frequencies of auditory and visual hallucination from 1830 to the end of the century. The presence of auditory hallucinations of people, when they occurred in males, significantly worsened the prognosis (P less than 0.025) compared to females. The findings are considered with special reference to the incidence and aetiology of schizophrenia in the last century.