Change in incidents of suicidal acts after intervention on a bridge in South Korea

To investigate whether two novel interventions on a bridge - a Video Incident Detection System (VIDS) and spinning bar barriers - have an impact on suicidal behaviour on the bridge.

A total of 146 suicidal acts were retrieved for analyses; 108 interventions before suicidal acts, 35 suicide deaths and 3 suicide attempts. Incident rate ratios (IRR) were calculated to estimate the change in incident rate associated with implementation of the two interventions: VIDS and the spinning bar 2-metre high barrier.

The results of the Poisson regression showed that the rate of suicide deaths, after installation the VIDS, did not change significantly (IRR: 1.23, 95% Confidence Interval [95% CI]: 0.59-2.56), although the rate of intervened suicidal acts increased (IRR: 2.40, 95% CI: 1.65-3.47). The results showed that subsequent spinning bar installation resulted in a decrease in the incident rate of intervened suicidal acts (IRR: 0.37, 95% CI: 0.25-0.57) as well as suicide deaths (IRR: 0.23, 95% CI: 0.07-0.71). Comparison of the period when both interventions were in place with the period with no interventions indicated a reduction in suicide deaths (IRR: 0.28, 95% CI: 0.10-0.82), but no change in intervened suicidal acts (IRR: 0.90, 95% CI: 0.59-1.38).

The rate of suicide death decreased after the installation of the spinning bar barrier but not after the implementation of VIDS alone. Our findings reinforce that restricting access to means is a highly effective way of preventing suicide on bridges and that spinning bars may be a helpful way to design barriers.