BackgroundRecent research has reported increased risk of aggressive incidents by individuals with psychotic illness.AimsTo examine acts of aggression in first-episode psychosis.MethodSubjects with a first-episode psychosis were ascertained from a defined catchment area (Nottingham, UK) and reassessed at 3 years (n=166) using clinical interview, informants, health care and forensic records.ResultsOf the subjects, 9.6% demonstrated at least one act of serious aggression (defined as weapon use, sexual assault or victim injury) during at least one psychotic episode and 23.5% demonstrated lesser acts of aggression (defined as all other acts of aggression). For all aggressive subjects (33.1%), unemployment (OR=3.6, 95%CI 1.6–8.0), comorbid substance misuse (OR=3.1, CI 1.1–8.8) and symptoms of overactivity at service contact (OR=6.9, CI 2.7–17.8) had independent effects on risk of aggression.ConclusionsWe confirmed some previously reported demographic and clinical associations with aggression in first-episode psychosis but no relationship with specific psychotic symptoms or diagnostic groups was observed.