Aggressive behaviour and psychosis in a clinically referred child and adolescent sample

Despite evidence of an increased risk of violence among adults suffering from psychosis, very little is currently known about
the relationship between early onset psychosis and aggressive behaviour. We aimed to identify and examine overlaps between
aggressive behaviour and psychosis in a referred child and adolescent sample to assess whether potential risk factors and
other associated features of this co-occurring pattern can be identified at a young age.

Standardised item sheet data on young people referred to the Child and Adolescent Department of the Maudsley Hospital between
1973 and 2004 were used to contrast three groups: (1) aggressive-only (n = 1,346), (2) psychosis-only (n = 173), and (3) co-occurring aggression and psychosis (n = 39) on a range of comorbid symptoms and potential risk factors.

Co-occurring cases presented with elevated rates of depersonalisation/derealisation, intrusive thoughts and restlessness,
and were more likely to have received past treatment compared with both psychosis-only and aggressive-only cases. Although
co-occurring cases resembled the psychosis-only group in many domains, including socio-demographic background and rates of
emotional symptoms, they differed from ‘pure’ psychosis cases in having high levels of special educational needs, irritability,
non-aggressive antisocial behaviours, as well as being more likely to be from a low social class and have increased contact
with police and child care authorities.

Our findings suggest that it is possible to identify early risk factors for aggression in individuals with psychosis.