Acute alcohol-induced impairment of cognitive functions: Past and present findings

Alcohol is arguably the most widely used and studied drug in human history. The acute effects of alcohol in humans have been studied in laboratories for over a century. Much of the interest in alcohol concerns its debilitating effects on human performance. Originally this interest was fueled by well-founded concerns that alcohol could impair the drinker's ability to operate an automobile. Before the advent of breath analysis devices, "road-side" behavioral tests of motor coordination and mental ability were the only means of detecting "impaired drivers". Thus there was much interest in discerning which aspects of human behavior were most disrupted by a given dose of alcohol. This paper concerns the acute impairing effects of alcohol on cognitive functions in healthy, non-alcohol dependent adults. The paper begins by describing how different aspects of human performance are not equally sensitive to the impairing effects of alcohol and that the wealth of research on these differences poses unique challenges for summarizing and communicating this large body of evidence. The paper then discusses speeded and divided attention tasks as methods commonly used to assess the acute cognitive impairing effects of alcohol and the cognitive theories that have been offered to account for the findings based on these tasks. This is followed by a review of more contemporary methods and techniques that focus on how the drug impairs specific cognitive mechanisms that underlie the control and regulation of behavior. The paper concludes by explaining how acute impairments of such mechanisms might actually contribute to the abuse potential of alcohol for some individuals.