Thirteen studies were included (n= 336,948, range 128 to 330,000).
Universal suicide prevention programmes (10 studies, n=334,209):
Most studies suffered from consistent methodological weaknesses: only 30% included reliable and valid measures; 10% demonstrated educational/clinical significant; 20% documented programme implementation fidelity; and none replicated the effects of the programmes. Eleven studies included a control group.
Most studies provided either weak (50%) or promising evidence (30%) for statistically significant outcomes.
Selected suicide prevention programmes (three studies, n=2,739):
All three studies included a control group, but suffered from consistent methodological weaknesses similar to those in the universal suicide prevention programmes. Only one study documented intervention adherence and used analytical techniques to identify which identifiable components of prevention programmes were related to statistical significance.
None of the studies showed promising or strong evidence for educational/clinical significance or the replication of effects.