A study sheds new light on what happens in the brain when a person with alcohol use disorder, or AUD, is presented with an opportunity for "delay discounting," namely forgoing a larger reward later in favor of a significantly smaller one sooner.
One of the questions asked in the study, published in the journal Alcohol and Alcoholism, to 17 alcohol-dependent individuals while their brain activity was monitored with functional magnetic resonance imaging, or fMRI, was: Would you rather receive 55 U.S. dollars today or 75 dollars two months from now?
In the research by psychological scientist Anita Cservenka of the Oregon State University (OSU) College of Liberal Arts and researchers at the University of California, Los Angeles, each subject read a series of 27 questions on a screen and had five seconds per question to answer via an electronic pad resting on his or her stomach.
As they lay still in the MRI tube, choosing a smaller amount of money sooner was categorized as an SS response; a larger amount later was classified as LL. On average, participants gave an SS response about two-thirds of the time, while fMRI more likely showed that he or she hadn't activated the "cognitive control" region of the brain as much as someone with a lower level of dependency would have.
Severity of dependence appeared to negatively correlate with activity in the cognitive control regions when participants make impulsive decisions: the more dependent someone is, the less active the control part of his or her brain is.
"If you just look at the behavior of individuals, those with more severe alcohol use disorder had a trend toward steeper delay discounting," Cservenka was quoted as saying in a news release from OSU on Monday. "How much they preferred smaller, immediate rewards was not significant, but it was a trend; the severity of the alcohol use disorder was positively associated with the wanting of smaller, immediate rewards."
In addition, the scans indicated dysregulation in other regions associated with decision making and higher-order cognition. The participants showed greater activation of the brain's reward-evaluation regions during "delayed decisions," namely choosing the larger, later prize. Activation of those regions during delayed decisions is positively associated with alcohol dependence severity, indicating that individuals with greater dependence may need to activate those areas more to make less impulsive decisions.
While impulsivity tends to decline with age, Cservenka noted, adults with severe alcohol use disorder can show heightened levels of impulsivity compared to individuals without alcohol use problems.
The findings suggest that more effective AUD treatment could involve neuropsychological tasks designed to help patients train themselves to make more-reasoned, better-planned decisions by using cognitive control to rein in impulses.
