Subthalamic high-frequency deep brain stimulation reduces addiction-like alcohol use and the possible negative influence of a peer presence

Abstract Rationale The immediate social context significantly influences alcohol consumption in humans. Recent studies have revealed that peer presence could modulate drugs use in rats. The most efficient condition to reduce cocaine intake is the presence of a stranger peer, naive to drugs. Deep brain stimulation (DBS) of the Subthalamic Nucleus (STN), which was shown to have beneficial effects on addiction to cocaine or alcohol, also modulates the protective influence of peer’s presence on cocaine use. Objectives This study aimed to: 1) explore how the presence of an alcohol-naive stranger peer affects recreational and escalated alcohol intake, and 2) assess the involvement of STN on alcohol use and in the modulation induced by the presence of an alcohol-naïve stranger peer. Methods Rats with STN DBS and control animals self-administered 10% (v/v) ethanol in presence, or absence, of an alcohol-naive stranger peer, before and after escalation of ethanol intake (observed after intermittent alcohol (20% (v/v) ethanol) access). Results Neither STN DBS nor the presence of an alcohol-naive stranger peer modulated significantly recreational alcohol intake. After the escalation procedure, STN DBS reduced ethanol consumption. The presence of an alcohol-naive stranger peer increased consumption only in low drinkers, which effect was suppressed by STN DBS. Conclusions These results highlight the influence of a peer’s presence on escalated alcohol intake, and confirm the role of STN in addiction-like alcohol intake and in the social influence on drug consumption.