Brain waves reveal how alcohol cues hijack decision-making in addiction

Alcohol use disorder disrupts decision-making processes by triggering automatic emotional reactions to alcohol-related cues. Research published in Progress in Neuropsychopharmacology & Biological Psychiatry indicates that the brain compensates for these cognitive disruptions by boosting activity in areas responsible for deliberate thinking.

Chronic substance use creates a disconnect between the reward centers and executive control regions of the brain, leading to a disproportionate emphasis on the addictive substance. Environmental cues, such as the sight of a bottle or familiar bar, become highly stimulating and dominate the brain's attention. In alcohol use disorder, a picture of a drink can immediately evoke a positive emotional response, operating below conscious awareness and making it harder to resist cravings.

This often results in relapses due to impaired ability to implement cognitive strategies. Traditional psychological tests measure basic reaction speed and accuracy, but do not capture the underlying cognitive steps involved in decision-making. To gain a deeper understanding, researchers use computational frameworks to break down decision-making into milliseconds and quantify variables such as information processing speed, decision-making threshold, and response execution time.

Electroencephalography, a technique that records electrical activity on the scalp, is used to track brain waves known as event-related potentials. These signals correspond to specific cognitive events and occur within fractions of a second. Early brain waves reflect unconscious attention, while later waves indicate conscious cognitive control.

Researchers sought to understand the sequence of neural and behavioral events in individuals with alcohol use disorder. A study conducted by Zijing Wang, Jiang Du, Tianzhen Chen, and Min Zhao at the Shanghai Mental Health Center mapped how early emotional biases affect later cognitive control and correlated brain wave patterns with decision-making speeds.

The study included 47 men diagnosed with alcohol use disorder and 32 healthy controls. Participants underwent an emotional association task on a computer, where they viewed pictures for a second, followed by a word that they had to categorize as positive or negative. During the task, sensor caps recorded their brain's electrical activity in real-time.

The researchers analyzed the behavioral data using a computational model to separate decision-making into three parts: decision threshold, drift rate, and non-decision time. Men with alcohol use disorder showed a lower decision threshold, indicating more impulsive choices requiring less mental evidence. Their drift rate was slower, meaning they were less efficient at processing visual information.

They also exhibited a longer non-decision time during alcohol trials, spending more time preparing to press the button. Electroencephalography data revealed heightened electrical responses in early brain waves around 200 to 260 milliseconds after alcohol-related images, indicating an automatic, unconscious sensitivity to alcohol cues.

This heightened neural activity can overwhelm a person's ability to shift attention. After viewing healthy activity images, the men with alcohol use disorder showed a larger late-stage brain wave response, suggesting conscious reallocation of mental resources.