Acute-alcohol effects on the Experiential Discounting Task (EDT) and a question-based measure of delay discounting

Alcohol is widely believed to increase impulsive behavior. However, this has been difficult to demonstrate for impulsive choice using existing measures of delay discounting. We hypothesized a new real-time discounting task would be more sensitive to acute effects of alcohol. Measures included were a (a) question-based measure of delay discounting, the (b) Experiential Discounting Task (EDT), the (c) Balloon Analogue Risk Task (BART), the (d) Stop Task, and the (e) Go/No-Go Task. A three-session, double-blind, placebo-controlled, within-subjects design was used. Placebo, 0.4, or 0.8 g/kg alcohol doses were administered in a counterbalanced order over the three testing sessions. Twenty four (13 females) healthy social drinkers between the ages of 21 and 35 participated. Alcohol increased impulsive responding only on the EDT and the Stop Task. On the EDT, participants performed more impulsively after the 0.8 g/kg dose compared to placebo, whereas on the Stop Task, both the 0.4 and 0.8 g/kg doses increased impulsive responding. Alcohol had no significant effects on the other measures. The EDT was more sensitive to the acute effects of alcohol than previously used discounting tasks. Procedural differences between the EDT and question-based measures are discussed in the context of these divergent findings.