Despite the breadth of research examining the relationship between impulsivity and alcohol use initiation, maintenance, and development of AUDs, the issue of causality in this relationship remains ambiguous. For example, studies in the majority of areas reviewed do not provide sufficient evidence to ascertain whether impulsivity predates AUDs as a risk factor, whether impulsivity co-occurs with AUDs perhaps a consequence or associated feature of persistent drinking, or rather co-exists as a result of a third common factor. Alternatively, impulsivity may be both a causative factor and a consequence of AUDs. Interactive effects often exist with both the genetic predisposition to impulsivity as well as effects of AUDs. For instance, an individual may have a predisposition to impulsivity, while certain consequences of excessive alcohol use (e.g., brain function abnormalities) may further exacerbate this predisposition. As noted above, biological research has made some progress teasing apart causality. Although still quite preliminary, there is more progress in this domain compared to studies using behavioral and self-report measures of impulsivity, where very limited progress has been made. Finally, to truly understand causality among these
