Predictive validity of the HCR-20 for inpatient aggression: the effect of intellectual disability on accuracy.
The HCR-20 forecasts inpatient aggression in adults with ID, yet the Clinical subscale lags, so weight the Historical score and skip the pills.
01Research in Context
What this study did
Austin et al. (2015) checked if the HCR-20 can forecast inpatient aggression in adults with intellectual disability.
They compared two groups: inpatients with ID and inpatients without ID.
Staff scored each patient on the 20-item tool and then tracked who became aggressive inside the unit.
What they found
The total score predicted aggression in both groups, but the effect was small.
The Historical and Risk subscales worked about the same for everyone.
The Clinical subscale lost power in the ID group; it flagged fewer future incidents.
How this fits with other research
Willner (2015) and Taylor (2002) both say medicines rarely curb aggression in ID. Their reviews line up with E’s call to rely on structured tools, not drugs.
Neuringer et al. (2007) and Levin et al. (2014) mapped aggression profiles and personality clusters in the same ID adults. E’s work extends theirs by showing the HCR-20 can turn those profiles into a usable risk number.
Van Hanegem et al. (2014) warned that dynamic factors may just echo static ones in forensic ID clients. The new inpatient data keep that caution: the Clinical subscale, full of dynamic items, under-performed, while the static-heavy Historical subscale held steady.
Why it matters
You can keep using the HCR-20 in ID services, but lean on the total and Historical scores. Treat the Clinical subscale as a prompt for staff discussion, not a hard predictor. Pair the tool with behavior plans, not extra meds, and you will target risk without side-effects.
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02At a glance
03Original abstract
BACKGROUND: People with intellectual disability (ID) account for a large proportion of aggressive incidents in secure and forensic psychiatric services. Although the Historical, Clinical, Risk Management 20 (HCR-20) has good predictive validity in inpatient settings, it does not perform equally in all groups and there is little evidence for its efficacy in those with ID. METHOD: A pseudo-prospective cohort study of the predictive efficacy of the HCR-20 for those with ID (n = 109) was conducted in a UK secure mental health setting using routinely collected risk data. Performance of the HCR-20 in the ID group was compared with a comparison group of adult inpatients without an ID (n = 504). Analysis controlled for potential covariates including security level, length of stay, gender and diagnosis. RESULTS: The HCR-20 total score was a significant predictor of any aggression and of physical aggression for both groups, although the area under the curve values did not reach the threshold for a large effect size. The clinical subscale performed significantly better in those without an ID compared with those with. The ID group had a greater number of relevant historical and risk management items. The clinicians' summary judgment significantly predicted both types of aggressive outcomes in the ID group, but did not predict either in those without an ID. CONCLUSIONS: This study demonstrates that, after controlling for a range of potential covariates, the HCR-20 is a significant predictor of inpatient aggression in people with an ID and performs as well as for a comparison group of mentally disordered individuals without ID. The potency of HCR-20 subscales and items varied between the ID and comparison groups suggesting important target areas for improved prediction and risk management interventions in those with ID.
Journal of intellectual disability research : JIDR, 2015 · doi:10.1111/jir.12184