Children and young people who disclose sensory experiences suggestive of hallucinations do pose a diagnostic and therapeutic challenge to mental health clinicians in their daily practice. Hallucinations, defined as erroneous percepts in the absence of identifiable stimuli, are a key feature of psychotic states, but they had also long been known to present in children with non-psychotic psychiatric
disorders. The recent upsurge of interest in childhood hallucinations has arisen out of epidemiological studies of child populations, where comprehensive symptom enquiry has included screening questions on abnormal perceptions. This has resulted in what seemed surprisingly high rates of hallucinatory
experiences among other psychotic-like symptoms. Children and ado
lescents show a prevalence rate of self-reported hallucinatory experiences of
about 10% and are reported as more common in childhood than in adolescence.
These hallucinatory phenomena are most likely to occur in the absence
of any psychiatric disorder and would be expected more often than not to be simpler, less elaborate and distressing than those observed in clinical samples of children with psychiatric disorders. Longitudinal studies have in fact shown that only a small proportion of children in the general population with hallucinations (less than 10%) will suffer from a psychotic disorder later in life. In
clinical settings, presentations with hallucinations can be an expression of a psychotic state, or alternatively of a symptom constellation co-occurr
ing along other psychiatric conditions. Associations have been found between hallucinations and traumatic stressors (i.e. bullying and sexual assault),
severity of psychopathology and suicidal symptoms. These associations could be mediated by individual vulnerability, involving neurodevelopmental
anomalies and a tendency to mental dissociation and mood dysregulation. This review details the clinical assessment of hallucinations in children and adolescents taking into account developmental considerations and paediatric
organic associations. It describes hallucinations in young people with psychoses (schizophrenic spectrum and mood disorders) and other non-psychotic
psychiatric disorders (emotional and behavioural disorders), and it addresses therapeutic aspects.