Alcohol-induced blackouts may be linked to how a person drinks, not just how much

Certain drinking behaviours beyond just the quantity of alcohol consumed may predict the likelihood a person will experience an alcohol-induced blackout, a condition where someone is conscious and engaging with their surroundings but will be unable to remember some or any of what occurred. Alcohol-induced blackouts (AIBs) are common in college students and individuals with AIBs are more likely to experience acute and chronic alcohol-related consequences.
A study published in Alcohol, Clinical and Experimental Research analysed data from 79 college sophomores and juniors who typically drank four or more drinks on a weekend day and had experienced at least one alcohol-induced blackout during the past semester. The students wore wristwatch-like devices with transdermal alcohol concentration sensors, which measured intoxication levels through the skin on 12 weekend days. The students also completed daily diaries each morning to assess their memories of the prior day.
Over the 12-day period, the sensors detected a total of 486 days of alcohol use, and students together reported 147 alcohol-induced blackouts. Seventy percent of the students experienced at least one alcohol-induced blackout, with 80 percent of female students and 70 percent of male students reporting experiencing a blackout. The students who reported at least one blackout had, on average, 2.2 alcohol-induced blackouts during the 12 days.
The researchers found that the speed with which college students become intoxicated, how long their intoxication levels were increasing, and their peak intoxication were each associated with experiencing an alcohol-induced blackout. They say that considering how an individual drinks (assessed using TAC biomarkers), rather than quantity alone, is important for assessing risk and has implications for efforts to reduce risk.
Source: Veronica L. Richards et al, Transdermal alcohol concentration features predict alcohol‐induced blackouts in college students, Alcohol, Clinical and Experimental Research (2024). doi.org/10.1111/acer.15290