Strategies for preventing suicide.

BACKGROUND: The Health of the Nation includes a target for reducing population suicide rates. We have examined and quantified various high-risk and population-based strategies for prevention based upon a number of stated assumptions and hypothetical interventions.
METHOD: The published literature was used to estimate the population attributable fractions for both high-risk and population-based strategies. The number needed to treat for the high-risk strategies was calculated, assuming an intervention that reduced suicide rates by 25%.
RESULTS: Interventions that would reduce rates of suicide by 25% would reduce population rates by about 2.6% for those recently discharged from hospital and by up to 5.8% for those presenting to general hospital with deliberate self-harm. The population attributable fraction for unemployment was 10.9%.
CONCLUSIONS: High-risk strategies will have only a modest effect on population suicide rates, even if effective interventions are developed. Evaluating interventions for deliberate self-harm patients seems worthwhile. The UK Government's target for suicide reduction is more likely to be achieved using population-based strategies. Reducing the availability of methods commonly used for committing suicide is the most practicable current policy, although more radical approaches, for example reducing unemployment, may also substantially reduce suicide rates.