Researchers at the National National Institute on Alcohol Abuse and Alcoholism (NIAAA) conducted a recent study that examined the effects of heavy drinking on the brain and how behavior may be affected as a result.
The study included 48 participants – twenty-four healthy persons and sixteen heavy drinkers.
Dr. Gene-Jack Wang, a nuclear medicine specialist, senior clinician and clinical director at the NIAAA, as reported by Addiction Now:
“Our sample has given us a chance to understand heavy drinkers better but not alcoholics. These were functional heavy drinkers, but we can see that even if the person does not become an alcoholic, their brain can already be showing signs of connectivity issues. Heavy drinking affects the brain tremendously.”
Heavy drinkers included in the study consumed at least five alcoholic drinks per day, three or more times per week. The control had a history of light drinking but did not have more that one drink per day. Subjects were randomly selected to drink either alcohol or a deceptive placebo that looked and smelled like alcohol.
Researchers used magnetic resonance imaging (MRI) scans to evaluate the effects of alcohol on resting brain activity. At the onset of the scanning session, the average blood alcohol concentration (BAC) was .62 milligrams.
About 90 minutes after alcohol/placebo consumption and 30 minutes before every MRI scan, researchers conducted motor and cognitive assessments to evaluate the effects of the consumed drink on the subjects' behavior.
Also, they administered self-reports about these effects on the participants' mood and collected data on topics such as levels of desire for alcohol, anxiety dizziness, intoxication, irritability, stimulation, sedation, self-confidence, and restlessness. Motor function was evaluated using tasks such as standing on one leg.
Researchers found that heavy drinking exhibited significantly lower levels of neurocognitive coupling, which is defined as the link between brain activity and behavior. In both groups, consumption of alcohol was revealed to alter the functional connectivity of areas in the brain including the precuneus and thalamus, which responsible for transmitting around 98% of all sensory impulses, and also regulates sleeping, alertness, and consciousness.
Overall, the study revealed that heavy drinkers had higher cerebellar connectivity but decreased cortical brain connectivity. This resulted in lower levels of cognitive ability. Drinkers themselves reported higher levels of desire for alcohol, irritability, restlessness, and decrease motor function.
~ G. Nathalee Serrels, M.A., Psychology