BackgroundAn increased rate of premorbid impairment has been reported in both child- and adolescent-onset schizophrenic and affective psychoses.AimsTo examine the evidence for a specific association between premorbid impairment and child- and adolescent-onset schizophrenia, and whether specific continuities exist between premorbid impairments and psychotic symptom dimensions.MethodRetrospective case note study of 110 first-episode child- and adolescent-onset psychoses (age 10–17 years). DSM–III–R diagnoses derived from the OPCRIT algorithm showed 61 with schizophrenia (mean age 14.1 years) and 49 with other non-schizophrenic psychoses (mean age 14.7 years).ResultsPremorbid social impairment was more common in early-onset schizophrenia than in other early-onset psychoses (OR 1.9, P=0.03). Overall, impaired premorbid development, enuresis and incontinence during psychosis were specifically associated with the negative psychotic symptom dimension.ConclusionsPremorbid social impairments are more marked in child- and adolescent-onset schizophrenia than in other psychoses. There appears to be developmental continuity from premorbid impairment to negative symptoms.