Investigating the behavioral and self-report constructs of impulsivity domains using principal component analysis

Impulsivity, often defined as a human behavior characterized by the inclination of an individual to act on urge rather than thought, with diminished regard to consequences, encompasses a range of maladaptive behaviors, which are in turn affected by distinct neural systems. Congruent with the above definition, behavioral studies have consistently shown that the underlying construct of impulsivity is multidimensional in nature. However, research to date has been inconclusive regarding the different domains or constructs that constitute this behavior. In addition there is also no clear consensus as to whether self-report and laboratory based measures of impulsivity measure the same or different domains. This study aimed to: (i) characterize the underlying multidimensional construct of impulsivity using a sample with varying degrees of putative impulsivity related to substance misuse, including subjects who were at-risk of substance use or addicted (ARA), and (ii) assess relationships between self-report and laboratory measures of impulsivity, using a principal component-based factor analysis. In addition, our supplementary goal was to evaluate the structural constructs of impulsivity within each group separately (healthy and ARA). We used five self-report measures (Behavioral Inhibition System/Behavioral Activation System, Barratt Impulsivity Scale-11, Padua Inventory, Zuckerman Sensation Seeking Scale, and Sensitivity to Punishment and Sensitivity to Reward Questionnaire) and two computer-based laboratory tasks (Balloon Analog Risk Task and the Experiential Discounting Task) to measure the aspects of impulsivity in a total of 176 adult subjects. Subjects included healthy controls (n = 89), nonalcoholic subjects with family histories of alcoholism (family history positive; n = 36) and both former (n = 20) and current (n = 31) cocaine users. Subjects with a family history of alcoholism and cocaine abusers were grouped together as 'at-risk/addicted' (ARA) to evaluate our supplementary goal. Our overall results revealed the multidimensional nature of the impulsivity construct as captured optimally through a five-factor solution that accounted for nearly 70% of the total variance. The five factors/components were imputed as follows 'Self-Reported Behavioral Activation', 'Self-Reported Compulsivity and Reward/Punishment', 'Self-Reported Impulsivity', 'Behavioral Temporal Discounting', and 'Behavioral Risk-Taking'. We also found that contrary to previously published reports, there was significant overlap between certain laboratory and self-report measures, indicating that they might be measuring the same impulsivity domain. In addition, our supplemental analysis also suggested that the impulsivity constructs were largely, but not entirely the same within the healthy and ARA groups.