Objective: Although there may be an increased risk of aggression in first-episode psychosis, little is known about the clinical and cognitive associations of serious and less serious aggression during this phase of psychotic illness.
Methods: Eighty-five patients in the first episode of psychosis under the age of 26 underwent comprehensive clinical assessment and cognitive testing. Aggression was assessed using a purpose-designed rating scale based on corroborative interviews to record 10 types of aggressive behaviour in the 3 months before presenting for treatment.
Results: Thirty-seven of 85 patients (43.5%) exhibited physically aggressive behaviour and 23 patients (27.1%) had assaulted another person or used a weapon. Young age and elevated scores in the mania rating scale were associated with a history of any type of aggression. Serious aggression was associated with regular cannabis use and more errors of commission on a continuous performance task.
Conclusions: The clinical features associated with less serious aggression were different to those associated with more serious forms of aggression. Serious aggression is associated with regular cannabis use and also reduced behavioural inhibition. Awareness of substance use and neurocognitive deficits may assist in the identification of potentially violent patients.