Recent quantitative genetic research on psychotic experiences: new approaches to old questions

•Psychotic experiences (PEs) are normal experiences that at the extreme are symptoms of psychosis.•The causal pathways underlying PEs in young people are a new focus of research.•PEs are moderately heritable and show considerable environmental influence.•Severe, frequent PEs appear genetically linked to less severe, less extreme PEs.•The genetic association between schizophrenia and PEs is now being tested.

It is common, particularly in young people, to report psychotic experiences (PEs) such as feeling paranoid and having hallucinations. The questions of the role of genes and environment on PEs in the general population, and how PEs relate to schizophrenia, have not, until recently, been addressed empirically. New approaches demonstrate the heritability and role of the environment on the full range of PEs (including positive, cognitive and negative types) and show that extreme, severe forms are linked genetically to milder, less severe forms. New approaches have tested whether PEs are associated with the genome-wide significant genetic variants known to predict schizophrenia. Although at an early stage, this research will impact how we understand PEs in everyday life.