Personality and the effects of acute alcohol intake. A contingent negative variation study in healthy subjects

This study investigates the relationship between blood alcohol concentrations (BACs) and contingent negative variation (CNV). Fourteen healthy subjects were divided on the basis of their personality profiles - the Minnesota Multiphasic Personality Inventory (Hs+Hy+D/3) - into a high score (HS) and low score (LS) subgroup. The CNV was recorded using a choice-reaction time (RT) task. CNV recording was performed in two conditions: inter-stimulus intervals (ISIs) of 1500ms and 2500ms at three different BACs (0.3, 0.5 and 0.8 g/L) after acute alcohol administration. At the high BAC (0.8 g/L), both subgroups showed a reduced CNV amplitude area and a longer RT (p<.05) in both ISI conditions. No effects either on the CNV or on the RT were observed at the low BAC (0.3 g/L). At the intermediate BAC (0.5 g/L), the HS subgroup displayed an increased CNV amplitude (p<.05), not accompanied by a significantly longer RT (short ISI condition), and a reduced late CNV (p<.05) with a longer RT (p<.05) (long ISI condition). In the LS group, only a longer RT was observed in the long ISI condition. CNV modifications point to an individual, apparently personality-related, threshold of sensitivity to different alcohol levels.