Failure to be explicit and comprehensive about the standardized measures under study could have led to very different conclusions about whether GABRA2 is associated with ‘impulsivity’ in this sample. If only the Barratt Impulsivity scales had been included, one might have concluded that there was no evidence of association with impulsivity. Yet, we do find association with sensation-seeking and extraversion in the adolescent samples. Previous investigators have also noted the importance of distinguishing between various constructs related to impulsivity. A systematic empirical investigation of many existing measures of impulsivity found five different factors describing dispositions to rash action that were only moderately related to each other (Cyders & Smith, 2007; Cyders et al., 2007). Two of the five dispositions were emotion-based: positive urgency is the tendency to act rashly when experiencing extremely positive mood and negative urgency is the tendency to act rashly when experiencing extremely negative mood. Two were based on deficits in conscientiousness: lack of planning is the tendency to act without forethought and lack of perseverance reflects a failure to tolerate boredom or to remain focused despite
