This chapter explores the current knowledge on the long-term development and outcome of adolescents with psychotic disorders. The outcome of individuals with schizophrenia and other psychotic illnesses has long been considered extremely poor, especially with illness onset in childhood or adolescence. We find evidence of cognitive deficits, lower educational level, and lower labor market affiliation among adolescents with psychosis compared to the general population. Furthermore, we find increased risk of substance abuse among these patients as well as increased risk of mortality and suicidality among adult patients with psychosis. However, current knowledge indicates that in the long-term, a substantial part of adolescents diagnosed with psychotic disorders manage or recover from their illness and have outcomes similar to individuals with illness onset later in life. Early intervention services, including treatment of substance abuse and suicide prevention, are therefore critical and hold promise for improved long-term outcome for these patients.