Dimensions of impulsive behaviour in abstinent alcoholics

Impulsivity is a complex multidimensional behavioural construct that has been frequently implicated in the pathogenesis of addictive disorders. Both self-report and behavioural measures have been developed to assess its underlying dimensions but their interrelation is still poorly understood and few studies have employed a comprehensive set of measures within a given population to explore their interrelation. In a stably abstinent alcohol-dependent population we explored the interrelations between two well known personality questionnaires (BIS-11 and SSS), and two behavioural measures reflecting different dimensions of impulsivity, behavioural disinhibition (Go/NoGo task) and delay discounting (DDT). In addition, we included the Iowa Gambling Task (IGT), a neurobehavioural measure of decision-making, a cognitive dimension that is closely related to impulsivity. Strong correlations were found between the different subscales of the self-report measures. However, the correlations between the behavioural measures and the self-report measures were weak, suggesting that they both tap into different aspects of the concept. Finally, a principal component analysis on the data of the behavioural measures revealed that they all loaded on separate factors. These findings support the hypothesis that behavioural disinhibition and delay discounting are two independent dimensions of impulsivity and that decision-making is a third cognitive dimension, independent of both other measures.