Anti-social personality characteristics and psychotic symptoms: Two pathways associated with offending in schizophrenia.

Background: Several research groups have shown that people with schizophrenia who offend do not form a homogenous group. A three-group model claimed by Hodgins proposes distinguishing between people who start offending before the onset of psychosis (early starters), after psychosis onset but at age 34 years or under (late starters) and after psychosis onset but at age 35 years or older (late first offenders).

Aims: This study aimed to test the hypotheses (1) that the personality of early starters and non-psychotic offenders would be similar, but different from either late-starter group; (2) that the late-starter groups would be more likely to have positive psychotic symptoms than non-criminal patients with schizophrenia; and (3) that symptom types would differentiate the psychotic groups.

Methods: A retrospective file study was conducted on cases of 97 early starters, 100 late starters and 26 late first offenders all drawn from the Netherlands Institute of Forensic Psychiatry and Psychology (NIFP) archives 1993-2008, 115 non-psychotic offenders from 2005-2008 NIFP archives and 129 patients with schizophrenia and no criminal history from one general service in Rotterdam.

Results: Early starters closely resembled the non-psychotic offenders in their premorbid anti-social personality characteristics. The two late-onset offending psychosis groups were more likely to have persecutory and/or grandiose delusions than non-offenders with psychosis, but so were the early starters.

Implications: In a first study to compare subgroups of offenders with psychosis directly with non-psychotic offenders and non-offenders with psychosis, we found such additional support for a distinction between early and late starters with psychosis that different treatment strategies would seem indicated, focusing on personality and substance misuse for the former but psychotic symptoms for all. It remains to be seen whether the higher rate of alcohol misuse amongst late first offenders is a fundamental distinction or a function of age difference.