Predicting institutional violence in offenders with intellectual disabilities: the predictive efficacy of the VRAG and the HCR-20.
BACKGROUND
There is a developing evidence base to support the use of risk assessment instruments in offenders with intellectual disability (ID). The aim of this study was to try to develop this literature with the inclusion of a control group of mentally disordered offenders without an ID, using the HCR-20 and VRAG.


METHODS
The VRAG and the HCR-20 were completed for a group of offenders with an ID (n = 25) and a control group (n = 45), in four medium-secure units across the UK. The outcome measure was physical aggression measured over 6 months.


RESULTS
Both instruments consistently produced large effect sizes predicting any physical aggression and severe physical aggression. The structured clinical judgement based on the HCR-20 was especially good.


CONCLUSIONS
The HCR-20 and the VRAG have excellent predictive efficacy in offenders with an ID. A structured clinical judgement based on the HCR-20 was especially predictive.
Partnerships in Care, Abergavenny, UK. Suzanne.Fitzgerald2@partnershipsincare.co.uk
Suzanne
S
Fitzgerald
Nicola S
NS
Gray
Regi T
RT
Alexander
Ruth
R
Bagshaw
Paul
P
Chesterman
Phillip
P
Huckle
Susan K
SK
Jones
John
J
Taylor
Tegwyn
T
Williams
Robert J
RJ
Snowden
D000328:Adult; D057237:Criminals / Q000331:legislation & jurisprudence / Q000523:psychology*; D005260:Female; D005555:Forensic Psychiatry / Q000295:instrumentation; D006801:Humans; D008607:Intellectual Disability / Q000523:psychology*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011329:Prisoners / Q000331:legislation & jurisprudence / Q000523:psychology; D011446:Prospective Studies; D011569:Psychiatric Status Rating Scales / Q000592:standards*; D018570:Risk Assessment; D055502:Secondary Prevention; D014754:Violence / Q000331:legislation & jurisprudence / Q000523:psychology*; D055815:Young Adult
actuarial measures; intellectual disabilities; risk assessment; structured clinical judgement