Violence and psychosis. I. Risk of violence among psychotic men.

A survey of the records of 1241 men remanded in prison on criminal charges over four months yielded a high prevalence of psychiatric disorder. Of the total prison intake of 2743 men over the same period, 246 (9.0%) showed major symptoms of psychiatric illness and a further 237 (8.6%) symptoms of withdrawal from drugs or alcohol. Symptoms of neurotic disorders were underrecorded, so in terms of diagnosis 237 men (8.7%) were considered to be psychotic. Of these, 166 (70%) were schizophrenic. The influence of affective psychosis was small. The risk of violence among men with schizophrenia was high. Twenty five (9%) non-fatal personal assaults and 24 (21%) offences of damage to property were committed by men with schizophrenia. The presence of mental illness probably influences the decision to remand in custody for some of these offences, but this is unlikely to explain the substantially higher prevalence of schizophrenia among men convicted of homicide (five (11%) ) and arson (six (30%) ) than would be expected in the general population of Greater London (0.1-0.4%). The prevalence of schizophrenia among men convicted of homicide may even be an underestimate, as may the prevalence of affective psychosis and possibly of other psychiatric abnormalities, given the substantial incidence of concurrent suicide in such men.