Background: There has been growing interest in the clinical and biological links between autistic spectrum disorder and psychotic disorders, and between symptoms of these disorders that exist below diagnostic thresholds. Whilst autism and schizophrenia are regarded as distinct disorders, recent studies support an overlap in the genetic architecture across these conditions. Although early neurodevelopmental impairment is associated with psychotic disorders in later life, evidence from longitudinal studies of the relationship between autistic traits and psychotic experiences is limited. Aims The aim of the study is to explore whether children with early autistic traits (social interaction and communication problems, and restricted, repetitive interests and behaviours) are more likely to present with psychotic experiences in early adolescence.

Method: Longitudinal study using the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort. The mothers of 8232 children were asked about autistic traits in their children as part of the Development and Well-Being Assessment (DAWBA) at the age of 7. Of those, 6439 children completed a semi-structured clinical assessment for psychotic experiences at the age of 12.

Results: Children whose mothers had concerns about autistic traits in early life, in particular with regard to speech development or 'rituals'/'habits', were more likely to develop psychotic experiences in early adolescence. The greater the number of early autistic traits a child had, the greater their risk of developing psychotic experiences. These associations were not confounded by IQ, family history of depression or schizophrenia, gender or socio-demographic characteristics.

Conclusions: Childhood autistic traits, and particularly speech problems and odd rituals or unusual habits, are associated with psychotic experiences in adolescence. This may be a result of a shared aetiology or because autistic traits may also be an early precursor of psychotic experiences.