Predictive accuracy of the Historical-Clinical-Risk Management-20 for violence in forensic psychiatric wards in Japan.

BACKGROUND: Most structured assessment tools for assessing risk of violence were developed in Western countries, and evidence for their effectiveness is not well established in Asian countries. AIMS: Our aim was to examine the predictive accuracy of the Historical-Clinical-Risk Management-20 (HCR-20) for violence in forensic mental health inpatient units in Japan.
METHODS: A retrospective record study was conducted with a complete 2008-2013 cohort of forensic psychiatric inpatients at the National Center Hospital of Neurology and Psychiatry, Tokyo. Forensic psychiatrists were trained in use of the HCR-20 and asked to complete it as part of their admission assessment. The completed forms were then retained by the researchers and not used in clinical practice; for this, clinicians relied solely on national legally required guidelines. Violent outcomes were determined at 3 and 6 months after the assessment. Receiver operating characteristic analysis was used to calculate the predictive accuracy of the HCR-20 for violence.
RESULTS: Area under the curve analyses suggested that the HCR-20 total score is a good predictor of violence in this cohort, with the clinical and risk sub-scales showing good predictive accuracy, but the historical sub-scale not doing so. Area under the curve figures were similar at 3 months and at 6 months.
CONCLUSIONS: Our results are consistent with studies previously conducted in Western countries. This suggests that the HCR-20 is an effective tool for supporting risk of violence assessment in Japanese forensic psychiatric wards. Its widespread use in clinical practice could enhance safety and would certainly promote transparency in risk-related decision-making.