“…Both convenience and random sampling methods were used in the cross‐sectional studies. Only six out of the 20 studies reported separate results for males and females (Afifi et al, ; Arenliu et al, ; Chin & Choi, ; Cho, Hallfors, & Iritani, ; Epstein, & Spirito, ; Peltzer, & Pengpid, ; Swahn et al, ). Finally, three studies explored the association between suicidal behavior and age at onset of substance use (Epstein & Spirito, ; Peltzer & Pengpid, ; Swahn et al, ).…”