Mental disorder and violence. A special (high security) hospital study

From a first clinical description of a complete resident sample of special (high security) hospital patients, we examined the association between mental disorder and violence.

A record survey of all 1740 patients resident at any time between 1 January and 30 June 1993, inclusive, and, for most, the official criminal record.

1015 patients (58%) had functional psychosis, one-quarter of whom also had an independent personality disorder; 461 (26%) had personality disorders uncomplicated by psychosis, and 264 (16%) had learning disabilities. Pre-admission substance misuse, which was probably under-recorded, had been most common among those with psychosis and an independent personality disorder. Less than 10% had never been convicted of a criminal offence, although 25% had been admitted directly from other hospitals. Direct personal violence was more common among men, and fire-setting among women. Schizophrenia was most strongly associated with personal violence. More than 75% of those with a psychosis were recorded as being driven to offend by their delusions. In the absence of delusions, hallucinations had no such effect.

For people with personality disorder better clinical descriptions seem essential. For people with a pure psychosis, as symptoms were usually a factor driving the index offence, treatment appears as important for public safety as for personal health.