Effect of Alcohol on the Sense of Agency in Healthy Humans
Even at low to moderate doses, ingestion of the widely used recreational drug alcohol (ethanol) can impact cognitive and emotional processing. Recent studies show that the sense of agency (SoA; ie, the subjective experience of voluntary control over actions) can be modulated by specific pharmacological manipulations. The SoA, as quantified by the intentional binding (IB) paradigm, is enhanced by direct or indirect dopaminergic agonists in patients with Parkinson’s disease and by ketamine (an N‐methyl‐D‐aspartate (NMDA) receptor antagonist) in healthy individuals. These findings implicate dopaminergic and glutamatergic neurotransmission in mechanisms underlying SoA. Alcohol has a complex set of actions, including disinhibition of dopaminergic neurotransmission and allosteric antagonism at NMDA receptors.
This study tested the hypothesis that low to moderate doses of alcohol would enhance SoA, and impact impulsivity and subjective emotional state. The researchers conducted two experiments in 59 healthy male and female “social alcohol users”, who ingested either a placebo “vehicle,” or one of two doses of ethanol: 0.4 and 0.6 g/kg. The doses of alcohol were proportional to their BMI to produce blood alcohol concentrations within the legal limits for driving in England and Wales.
In both experiments, researchers observed increased SoA/IB at both doses of alcohol exposure, relative to the placebo condition. The study found no correlation between the effects of alcohol on IB and on impulsivity or subjective emotional state.
The findings might have implications for social and legal responsibility related to alcohol use, particularly in states prior to intoxication. Further studies are necessary to investigate the effects of alcohol and other addictive substances on the SoA.
Our study presents a compelling case that even one pint of beer is enough to significantly compromise a person’s sense of agency. This has important implications for legal and social responsibility of drivers, and begs the question: are current alcohol limits for driving truly safe?,” said Dr Silvana De Pirro, lead author of the research paper, as per, University of Sussex News.
It’s important to note that in our experiments, all the participants stayed within the legal alcohol limit for driving in England, Wales, the US and Canada. And yet we still saw an impairment in their feeling of being in control, said Professor Aldo Badiani, Director of the Sussex Addiction Research and Intervention Centre (SARIC), as per University of Sussex News.
In England, Wales and North America, the argument to lower the limit has much momentum. The results of our study support the implementation of such a change in the law.”