Evaluation of a Suicide Risk Assessment Tool in a Large Sample of Detained Youth.

Objectives: We evaluated the six-item Inmate Security Assessment (ISA) tool used among detained youth in Manitoba, Canada.

Method: Two hundred and forty-one recorded self-harm incidents among all incarcerated youth occurred between January 1, 2005 and December 31, 2010 (N=5102). The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (PLR) and negative likelihood ratio (NLR) for three categories of suicide risk (high, medium, and low) as well as each of the six suicide risk evaluation indicators were determined. Receiver operating characteristic (ROC) curves and area under the curve (AUC) calculations for the three suicide risk levels and the six indicators were created.

Results: Having at least a low suicide risk level (93.8%) or at least one suicide risk factor (94.6%) provided high sensitivity. Specificity was high if an individual had at least a medium suicide risk level (94.2%) or at least three suicide risk indicators (96.7%). The PPV was low (8.9-16.2%) and the NPV was high (94.9-99.3%) for all suicide risk levels. The most sensitive risk factor for self-harm was a prior history of suicidal behavior or a family history of suicide (94.6%). All risk indicators had a low PPV (7.4-23.1%) and a high NPV (95.4-99.5%). A very low NLR was found for those without prior suicidal behavior or a family history of suicide (0.107). The AUC was 0.719 (95%CI = 0.692-0.746), indicating a fair test.

Conclusion: The ISA is a moderately accurate tool for identifying risk for self-harm in detained youth.