Psychopathological conditions in adolescence and young adulthood often result from an altered neurodevelopment already phenotypically expressed in childhood. Child and adolescent mental health services are ideally placed to intercept in the developmental trajectories of younger adolescents and contribute to the early detection of a risk for psychosis, as proposed by Salazar de Pablo and Arango (2023, Child and Adolescent Mental Health), opening a debate to which we contribute. The early detection of a specific risk for psychosis and of a broader risk for severe mental illness requires an understanding of the clinical staging of psychosis, neurodevelopmental antecedents of severe mental illness and of heterotypic trajectories between childhood phenotypes and adult disorders.