Effectiveness of barriers at suicide jumping sites: a case study.

Abstract

Suicide safety barriers were removed from a central city bridge in an Australasian metropolitan area in 1996 after having been in place for 60 years. The bridge is a known suicide site and is located adjacent to the region's largest hospital, which includes an acute inpatient psychiatric unit. This paper examines the impact of the removal of these barriers on suicide rates. Data for suicide deaths by jumping from the bridge in question, from 1992 to 2000, were obtained from the regional City Police Inquest Office. Data for suicide deaths by jumping from other sites in the metropolitan area in question, from 1992 to 1998, were obtained from the national health statistics database. Case history data about each suicide death by jumping in the metropolitan area in question, from 1994 to 1998, were abstracted from coronial files held by a national database. Removal of safety barriers led to an immediate and substantial increase in both the numbers and rate of suicide by jumping from the bridge in question. In the 4 years following the removal of the barriers (compared with the previous 4 years) the number of suicides increased substantially, from three to 15 (chi2 = 8, df = 1, p < 0.01); the rate of such deaths increased also (chi2 = 6.6, df = 1, p < 0.01). The majority of those who died by jumping from the bridge following the removal of the safety barriers were young male psychiatric patients, with psychotic illnesses. Following the removal of the barriers from the bridge the rate of suicide by jumping in the metropolitan area in question did not change but the pattern of suicides by jumping in the city changed significantly with more suicides from the bridge in question and fewer at other sites. Removal of safety barriers from a known suicide site led to a substantial increase in the numbers of suicide deaths by jumping from that site. These findings appear to strengthen the case for installation of safety barriers at suicide sites in efforts to prevent suicide deaths, and also suggest the need for extreme caution about the removal of barriers from known jumping sites.