Correlates of trait impulsiveness in performance measures and neuropsychological tests.

Performance measures of impulsiveness offer great promise for assessing this trait in clinical and experimental studies. However, little is known about their relative superiority or inferiority to standard cognitive performance measures as correlates of this trait. In this study, 58 healthy volunteers completed a self-rating of impulsiveness (Barratt Impulsiveness Scale) and a battery of neuropsychological tests. The test battery included measures of reaction time, attention, memory, fluency, and executive function, as well as two performance measures of impulsiveness--Time Estimation and a Go-No Go task. Self-ratings correlated moderately with a number of these test scores, but many correlations became non-significant after adjustment for age and education. Correlations with the Go-No Go task, verbal fluency, executive function measures (Trails B), and tasks requiring decision-making against time (Choice Reaction Time, Reaction Time to Paired Words and Paired Faces Memory Tasks, and response bias on the Continuous Performance Test) remained significant. Performance on the Go-No Go task was the strongest correlate of self-rated impulsiveness. The findings suggest that once general demographic or ability factors are accounted for, specialized performance tasks requiring decision-making and response organization under time pressure provide the most effective means of assessing this behavioral trait.