Response inhibition and reward response bias mediate the predictive relationships between impulsivity and sensation seeking and common and unique variance in conduct disorder and substance misuse

Background: Disinhibited traits, assessed both at the self-report and at the cognitive/behavioral levels, have been frequently implicated in externalizing behaviors, such as conduct disorder (CD), binge drinking, and drug use. However, self-report measures of disinhibition, such as impulsivity (IMP) and sensation seeking (SS), and cognitive measures of disinhibition are not often studied together in the same participants. Thus, it is still unclear how cognitive measures such as response inhibition and reward response bias relate to self-report measures of IMP and SS, and whether they can explain some of the association found between these self-report measures and specific facets of externalizing problems.

Methods: The aim of this study was to assess whether cognitive measures of disinhibition relate to self-report measures of disinhibition and can mediate the specific relationships between self-report measures of disinhibition and CD symptoms, binge drinking and drug use in adolescence. Seventy-six adolescents were assessed on personality, substance use, and conduct problems every 6 months from 14 to 16 years of age and completed a test battery that included a Stop task, rewarded go/no-go task, digit span, and intelligence quotient tests at 16 years of age.

Results: Multiple regression analyses showed that self-report IMP at 14 and deficits in response inhibition were associated with a 2-year average CD symptoms score and that deficits in response inhibition partially mediated the association between self-report IMP and CD symptoms (ab = 0.018 CI: 0.00002 to 0.04827). In contrast, SS and reward response bias were significantly associated with the unique variance in binge drinking, and that part of the overlap between SS and binge drinking was mediated by reward response bias (ab = 0.019, CI: 0.00131 to 0.04662).

Conclusions: Findings show a dissociation between inhibitory measures associated with CD symptoms and those associated with binge drinking, with "cool" inhibitory and executive functions being associated with CD but "hot," reward-related disinhibition measures being specific mediators between SS and binge drinking. The findings support the theoretical conceptualization for dual cognitive/motivational pathways of disinhibition, in this case IMP and SS, and their unique association with externalizing behavior in adolescence.