Suicidal intent in deliberate self-harm and the risk of suicide: the predictive power of the Suicide Intent Scale.

BACKGROUND: Suicidal intent at the time of deliberate self-harm (DSH) is known to be associated with risk of future suicide in DSH patients. The predictive power of suicidal intent to identify particular individuals who are at high risk of suicide is unclear.

METHOD: Clinical and demographic data on 4156 DSH patients presenting to hospital 1993 and 1997 were analysed. Follow-up information on eventual suicide was available for 2489 patients (mean follow-up 5.2 years). The predictive value of the Beck Suicidal Intent Scale (SIS) was examined using Receiver Operating Characteristic (ROC) plots.

RESULTS: Thirty males (2.9%) and 24 females (1.7%) died by suicide. Despite a robust association between suicidal intent and eventual suicide, the positive predictive value (PPV) of the SIS was low (4%). Predicted probabilities of suicide assigned to individual patients were also low, even for those who eventually died by suicide.

LIMITATIONS: Assessment and follow-up information was not available for all patients.

CONCLUSIONS: The SIS cannot predict which individual patients will ultimately die by suicide. Nonetheless, information regarding suicidal intent is valuable in the clinical risk assessment and management of DSH patients.