Highlights • Antisocial personality disorder was associated with increased risk for substance-impaired driving. • This relationship was attenuated by mechanism variables. • Observed attenuation of this relationship was almost entirely due to impulse control.

Abstract Introduction: Antisocial personality disorder is a risk factor associated with increased risk for substance-impaired driving. While past research has focused on identifying prevalence rates for the disorder among substance-impaired drivers, there is a dearth of research focused on identifying the mechanisms by which the disorder actually functions to increase risk for the behavior among young adults who were formerly adjudicated for a serious offense. There are cognitive, affective, and social mechanisms that may help to explain this relationship. Method: Impulse control, hostility, and deviant peer association are examined as mechanisms that explain the relationship in each of these domains, respectively. The Pathways to Desistance data were utilized in analyses, comprising the responses of 1,354 youth who were adjudicated for a serious offense just prior to baseline measurements. Generalized structural equation modeling was used to examine the direct effects of antisocial personality disorder on substance-impaired driving risk and the hypothesized mechanism variables were then included in the model to determine which of them provided significant pathways through which the main relationship operated. Results: Results indicated that meeting criteria for a diagnosis of antisocial personality disorder was associated with increased risk of substance-impaired driving at follow-up. This relationship was attenuated to non-significance upon inclusion of the mechanism variables and reduced in magnitude by 20%. This attenuation was due almost entirely to impulse control. Practical Applications: This provides indication that intervention for substance-impaired driving offenders with antisocial personality disorder may be most effective when structured around improving impulse control for young adults who were previously involved with the juvenile/criminal justice system.