Are hazardous drinkers more impulsive than light drinkers? A comprehensive assessment in young adults

Those with alcohol dependence are characteristically impulsive. It is unclear whether the same is true of hazardous drinkers (i.e., women routinely drinking more than 14 units in a typical week but fewer than 35, and men drinking more than 14 units but fewer than 50). Yet, it is important to understand the mechanisms involved in such drinking, since it places the drinker at risk for future harm. The present study thus comprehensively assessed whether impulsivity was elevated in hazardous drinkers, compared to lighter drinkers. An opportunity sample of 57 light and 49 hazardous drinkers was assessed on the following impulsivity subdomains (via the measures in parentheses): (i) trait impulsivity (the Barratt Impulsiveness Scale, Version 11); (ii) temporal impulsivity (the Monetary Choice Questionnaire); (iii) stopping impulsivity (the Stop-Signal Task); (iv) waiting impulsivity (the Continuous Performance Task or CPT); (v) reward-sensitivity (the Behavioural Activation Scales); and (vi) risk-taking (the Balloon Analogue Risk Task). Alcohol- and other drug-dependent individuals were excluded from the study, while socio-demographics (age, gender, and socio-economic status), mood, binge drinking, and nicotine intake were all controlled for. The groups were compared via a series of Bonferroni-corrected, independent-measures t tests. The results revealed that hazardous drinkers were more impulsive than light drinkers on the CPT; there were no other statistically significant group differences. Consistent with the above, a logistic regression, with drinking group as the dependent variable and the impulsivity indices as independent variables, revealed that only CPT performance was a significant predictor of drinking status. Other than gender, none of the control variables significantly correlated with CPT performance. A sequential linear regression revealed that drinking status continued to predict CPT performance, after first accounting for gender. Thus, from a battery of impulsivity measures, only waiting impulsivity (i.e., CPT score) was elevated in hazardous drinkers, relative to lighter drinkers. Waiting impulsivity may thus be important in the maintenance of hazardous drinking.