Removing bridge barriers stimulates suicides: an unfortunate natural experiment.
OBJECTIVE
Safety barriers to prevent suicide by jumping were removed from Grafton Bridge in Auckland, New Zealand, in 1996 after having been in place for 60 years. This study compared the number of suicides due to jumping from the bridge after the reinstallation of safety barriers in 2003.


METHODS
National mortality data for suicide deaths were compared for three time periods: 1991-1995 (old barrier in place); 1997-2002 (no barriers in place); 2003-2006 (after barriers were reinstated).


RESULTS
Removal of barriers was followed by a fivefold increase in the number and rate of suicides from the bridge. These increases led to a decision to reinstall safety barriers. Since the reinstallation of barriers, of an improved design, in 2003, there have been no suicides from the bridge.


CONCLUSIONS
This natural experiment, using a powerful a-b-a (reversal) design, shows that safety barriers are effective in preventing suicide: their removal increases suicides; their reinstatement prevents suicides.
Canterbury Suicide Project, Department of Psychological Medicine, University of Otago, Christchurch, Christchurch, New Zealand. annette.beautrais@yale.edu
Annette L
AL
Beautrais
Sheree J
SJ
Gibb
David M
DM
Fergusson
L John
LJ
Horwood
Gregory Luke
GL
Larkin
D001107:Architectural Accessibility; D001315:Australia / Q000453:epidemiology; D006801:Humans; D012449:Safety; D013405:Suicide / Q000706:statistics & numerical data*; D000092864:Suicide Prevention