Accurate diagnosis of psychotic disorders may be very difficult in youth with intellectual disabilities. The authors reviewed the assessment, treatment and follow-up of 21 youths with ID referred because of early onset of psychotic symptoms. Just over one half of the patients had a diagnosis of schizophrenia or schizo-affective disorder. One third of the sample carried the diagnosis of psychosis NOS (not otherwise specified). After careful review, five out of seven of these psychotic-like cases were assessed as non-psychotic. Patients with Psychosis NOS associated with moderate or severe ID had the worst outcome. This clinical review provides important information about the identification, diagnosis and outcome of psychotic symptoms in youth with low verbal abilities.