Considering empirical evidence, in cross-sectional studies, early smoking initiation and nicotine dependence have been associated with suicidal behavior (Hockenberry et al., 2010; Dong-Sik & Hyun-Sun., 2010; Swahn et al., 2012), but the associations may differ by sex (Cho et al., 2007; Brunner et al., 2007). Genetically informed designs, such as twin studies, have found risk factors for self-injury, such as alcohol use and bullying victimization (Few et al., 2015; Fisher et al., 2012). Studies among adults have confirmed an association between smoking and suicide in cross-sectional, clinical and prospective studies (Covey et al., 2012, 2009; Breslau et al., 2005), even after adjusting for confounders (Kessler et al., 2009). Smoking is longitudinally associated also with suicidal ideation, suicide attempts, and completed suicide among adults (Li et al., 2012, Evins et al., 2017). Smoking may increase the risk for future SRB independently of psychiatric comorbidity (Hintikka et al., 2001, Oquendo et al., 2007).
