There is strong evidence that rare copy number variants (CNVs) are associated with increased risk of schizophrenia (1-4) and autism (4-7), and a number of lines of evidence point to a shared genetic component to schizophrenia and autistic spectrum disorders. Aims: 1) To examine the frequency of CNVs within a population-based birth cohort. 2) To examine whether individuals with large/rare CNVs are at increased risk of developing autistic traits during childhood. 3) To examine whether individuals with large/rare CNVs show reduced cognitive ability during childhood and adolescence. 4)To examine whether individuals with large/rare CNVs are at increased risk of developing psychotic experiences during adolescence, and whether this association if present is mediated through autistic traits or impaired neurocognitive or social cognitive ability.

Hypotheses: We hypothesise that psychotic experiences, autistic traits, and impaired cognitive function will be more common in individuals with large, rare CNVs. We hypothesise that some CNVs will be shared across all neurodevelopmental outcomes (eg deletions in NRXN1), whilst others will show unique associations with these phenotypes. We hypothesise that autistic traits and impaired cognitive ability are unlikely to mediate any association between CNV burden and psychosis.

Outcomes: 1) Psychotic experiences at age 17 (definite psychotic experiences, and clinical/prodromal states). 2) Autistic traits. 3) Cognitive function.