Individual Differences in Alcohol Drinking Frequency Are Associated With Electrophysiological Responses to Unexpected Nonrewards

Background: It has been suggested that alcohol use is related to sensitivity of the reward system. Although there are several studies using self-reported measures supportive of this notion, objective biological data in humans on this issue are lacking. Aims: This study is designed to test whether alcohol drinking frequency is associated with electrophysiological indices of reward processing. Materials and Methods: In a passive gambling task, stimuli predicted the presence (reward) and absence (nonreward) of rewards resulting in P2 and medial frontal negativity (MFN) indices of reward processing. Forty-seven undergraduate students were asked about their habitual drinking frequency and the P2 and MFN to stimuli predicting reward were measured. Results: Most importantly, the MFN to unpredicted nonrewards at the frontal midline (Fz) location correlated significantly with drinking frequency, with frequent drinkers showing larger MFN amplitudes. The results did not show a significant association between frequency and alcohol drinking and P2. Discussion: Although several studies showing increased reward-sensitivity in addictive behaviors, the present results indicate that, in frequent alcohol drinkers, electrophysiological responsiveness is particularly activated by unpredicted nonrewards. In general, this may point to the involvement of the reward system in alcohol drinking frequency. Conclusion: More specifically, the results demonstrate an increased vulnerability of high frequency drinkers to signals of (frustrative) nonrewards.