Criminal conviction after discharge from special (high security) hospital. Incidence in the first 10 years.

BACKGROUND: The aim was to measure the criminal convictions received by people who leave special hospital and to test previously identified correlates of conviction.
METHOD: A cohort study design was used and the subjects were all 425 patients discharged from the special hospitals in 1982 and 1983. The outcome measure was a criminal conviction received within 10.5 years of discharge.
RESULTS: Five and a half years after discharge 26% of ex-patients had been convicted of any offence, 9% of a violent offence, 5% of a sex offence and 10% of any serious offence. Ten and a half years after discharge 34% of patients had been convicted of any offence, 15% of a violent offence, 7.5% of a sex offence and 15% of any serious offence. When other variables are controlled for, gender and destination on discharge do not predict conviction. Age, a legal category of psychopathic disorder and prior criminal record do predict, but the effect is small.
CONCLUSION: The rate of conviction of patients leaving special hospital has fallen over the past 20 years; this is the case for crime in general and for serious crimes in particular. The change in rates of conviction over time for patients of different legal categories, previously thought to be different, is the same. The low predictive power of the variables examined here suggests that actuarial methods are of limited value in predicting offending in this group.