Predicting suicide: A comparison between clinical suicide risk assessment and the Suicide Intent Scale

Background: How suicide risk should be assessed is under discussion with arguments for both actuarial and clinical approaches. The aim of the present study was to compare the predictive accuracy of a clinical suicide risk assessment to that of the Suicide Intent Scale (SIS) in predicting suicide within one year of an episode of self-harm with or without suicidal intent.

Methods: Prospective clinical study of 479 persons assessed in a psychiatric emergency department after an episode of self-harm. The clinical risk assessment and the SIS rating were made independently of each other. Suicides within one year were identified in the National Cause of Death Register. Receiver operating characteristic (ROC) curves were constructed, optimal cut-offs were identified and accuracy statistics were calculated.

Results: Of 479 participants, 329 (68.7%) were women. The age range was 18-95 years. During one-year follow up, 14 participants died by suicide. The area under the curve (AUC) for the clinical risk assessment and the SIS score were very similar, as were the accuracy statistic measures at the optimal cut-offs of the respective methods. The positive predictive value (PPV) of each assessment method was 6%.

Limitations: The clinical suicide risk assessment is not standardized. The number of suicides is small, not allowing for stratification by e.g. gender or diagnosis.

Conclusion: Predictive accuracy was similar for a clinical risk assessment and the SIS, and insufficient to guide treatment allocation.