Because of the frequent co-occurrence of suicidal behavior and substance abuse, there is a need to better understand the relationships between these behaviors (Erinoff et al. 2004), as well as the risk factors for these behaviors. Previous studies of the relationship between suicidal and substance use behaviors have focused on the degree to which drug abuse is associated with increased risk for suicidal behavior (Borges et al. 2001; Hawton et al. 1993; Pages et al. 1997; Rivara et al. 1997), and the relationship of substance use behaviors to both suicidal ideation (Levy and Deykin, 1989; Pages et al. 1997) and suicide attempts among adolescents and adults (Beautrais et al. 1997; Levy and Deykin, 1989). However, little is known about the risk factors that are associated with these behaviors. Some important gaps in the suicide literature are an understanding of when and how different risk and protective factors interact to influence the probability for suicidal behaviors and substance use. In the following sections, we first review specific risk factors of suicidal behavior and drug abuse, which includes impulse control and impulsive
