Alcohol-related blackouts during youth are markers of future neurocognitive risk

Alcohol-related blackouts (ARBs) are fairly common among younger, social drinkers – even considered a rite of passage by some. Yet new research has found that blacking out predicts unique, underlying brain changes involved with learning, memory, and the processing of visual information. These results will be discussed on Monday, 24 June 2024 at the 47^th annual scientific meeting of the Research Society on Alcohol (RSA) in Minneapolis, Minnesota.

“Alcohol-related blackouts tend to occur when an individual drinks a large amount of alcohol in a short period of time, resulting in a rapid increase in blood alcohol concentration,” explained Sara A. Lorkiewicz, Ph.D., at the Michael E. DeBakey VA Medical Center. “Individual factors such as drinking on an empty stomach, polysubstance use, biological sex, and genetic factors that regulate alcohol metabolism also mediate alcohol-related blackout risk.”

On a neurochemical level, she added, “alcohol disrupts mechanisms in brain regions such as the hippocampus – the area of the brain involved in learning and memory – that transfers sensory information – such as vision, smell, and sound – from short-term memory to long-term memory. In other words, new memories are not being formed. Intoxicated individuals have not passed out, but are consciously interacting with their environment, and later experience anterograde amnesia for some or all details from that drinking event.

Lorkiewicz examined a group of individuals ages 12 to 24, who were enrolled in the National Consortium on Alcohol and Neurodevelopment in Adolescence study, during a six-year period to better understand how alcohol impacts the brain during key developmental stages. The brain is particularly susceptible to alcohol use during adolescence and early adulthood, which is also when social development, educational milestones, and occupational achievements can be negatively impacted by even subtle changes in cognition.

“In the current study, we found that ARBs significantly predicted lower brain volume in the fusiform gyrus and in the hippocampus,” said Lorkiewicz. “In a prior study, ARBs also significantly predicted a diminished development of facial recognition and visual recall, which would essentially hinder one’s ability to efficiently learn and remember visual information, including people. In the real world, this may look like a lower-than-expected performance in school/work or inability to form social relationships.”

“Given how prevalent and accepted binge drinking is among adolescents and young adults,” said Lorkiewicz, “it is important to understand the potential risks involved with such behavior. This study has allowed us to look at the impact of blackouts across a six-year period and see how a seemingly innocuous phenomenon may indicate adverse, alcohol-related consequences in day-to-day life.”