Wang Hao-wei describes how the introduction of stricter gun controls in a certain US state, stipulating a wait of six weeks between registering to purchase a gun and actually obtaining the weapon, immediately cut the incidence of impulse suicides and led to a fall in the overall suicide rate. Similarly, it is said that there was a marked drop in suicides in Britain after that country began using non-toxic domestic gas.
王浩威指出，美國某州修改槍械管制制度，規定購買槍械要在登記六個星期後才可以取得，此規定一實施，減少了許多衝動型的自殺，自殺率因而下降；據說英國在採取煤氣去毒化處理後，自殺率也有明顯的下降。