Thirty-five studies addressed the association between smoking and suicidal ideation [25, 28, 30–62], 8 studies addressed the association between smoking and suicide plan [39, 40, 48, 49, 55, 59–61], 30 studies addressed the association between smoking and suicide attempt [25–27, 29, 30, 32, 34, 37–40, 43, 46–50, 55, 59, 61–71], and 16 studies addressed the association between smoking and suicide death [72–86]. The number of studies presented in the forest plots may be more than the total number of included studies. The reason is that some studies reported the association between smoking and different types of suicidal behaviors simultaneously.
