Before further detailing the relationships between impulsivity and addictions, it is crucial to note that there exist many conceptually and procedurally distinct measures of impulsivity and impulsive behaviors (Table 1). In a highly influential article, Evenden2 details the different theoretical approaches to measuring impulsivity, which have long held that impulsivity and impulsive behavior is not a singular phenomenon. The reasoning for a multi-factorial model of impulsivity starts with its descriptions and definitions. Beginning with the attempts of psychometricians and personality theorists to understand impulsive tendencies (or related phenomena) and extending into the descriptions of clinically-impairing impulsivity,48 there is a substantial variability in the characteristics that are viewed as indicators of it and in the forms in which it manifests. Many of these concepts and definitions were embedded into implementations of laboratory tasks that were designed to operationally measure forms of impulsive behavior (Table 1). One example is the divide between impulsive behavior that seems to reflect compromised ability to inhibit inappropriate behaviors (“impulsive action”) and a tendency to make choices leading to suboptimal immediate or unduly risky outcomes (“impulsive choices”), 20, 32, 55 as demonstrated in Table 1.20, 32, 55
