Several intriguing questions remain. Why do children start tobacco use at an early age? What are their relationships with their parents and peers like? Are their family environments characterized by negative attitudes towards life or by avoidance of responsibility? Do these factors correlate with future psychopathology, such as SRB’s? (Pulkkinen 1982). Analyses of discordant co-twins represent one way to explore the association of early-onset tobacco use with self-injurious behaviors while taking into account familial confounds. Scherrer et al. (2012) suggested that contributions from familial factors may not significantly alter the association of smoking with SRB. In our study, we did not fully replicate the individual based analyses in the discordant twin design. Thus, longitudinal associations between early-onset tobacco use and SRB may partly be explained by differences in family environments. Other family studies are encouraged to investigate these associations further. If confirmed, these novel findings may have important implications for treatment and prevention programs.
