Genetics of psychotic disorders with focus on early-onset psychosis

Psychotic disorders have a high heritability and a complex genetic architecture, composed by multiple genetic factors interacting with the environment. In recent years, large-scale studies have identified multiple common (polygenic) and rare risk variants associated with the psychotic disorders schizophrenia and bipolar disorder. Research on youth with early-onset psychosis supports a higher heritability than adult-onset psychotic disorders and a substantial genetic overlap with schizophrenia and other neurodevelopmental disorders, as well as a higher load of rare highly penetrant variants. Thus knowledge of the etiology of early-onset psychosis might be scientifically informative for psychotic disorders in general, representing a subgroup with a high biological vulnerability. Translation of the identified genetic loci into pathobiological mechanisms can inform the development of better pharmacological agents and facilitate precision medicine approaches. For the significant minority with highly penetrant variants, genetic testing and counseling might improve awareness of relevant comorbidities and family planning.