Study Finds Blackouts Attributed To More Than Alcohol Quantity

When It Comes To Blacking Out, How You Drink May Matter More Than How Much You Drink

Alcohol-induced blackouts (AIBs) are defined as gaps in memory for events that occurred while intoxicated. They are particularly dangerous since a person experiencing an AIB can still perform everyday activities such as driving, walking, and engaging in conversation. AIBs are most frequently associated with the amount of alcohol consumed; however, while that certainly plays a part, a new study has found that it may not be the only cause for experiencing a blackout.

A 2024 study from the journal Alcohol, Clinical and Experimental Research collected data from 79 college students who were classified as “risky” drinkers based on the inclusion criteria of being between 18-22 years of age, being in their second or third year of college, having experienced a blackout during the previous semester, and regularly drinking four or more drinks on Friday or Saturday.

These participants wore transdermal alcohol concentration (TAC) sensors and self-reported in diary entries over four weeks. The TACs were used to measure biomarkers of alcohol intoxication, including:

• Speed of intoxication (a rapid rise in BAC)
• Peak intoxication level (level of intoxication reached)
• Time spent reaching peak intoxication level

At the study’s conclusion, the researchers found that all three biomarkers independently contributed to AIBs, meaning that even if only one biomarker was heightened, there was a likelihood of experiencing an AIB.

A Dangerous Habit

Blackouts occur when a person ingests enough alcohol to briefly block the transfer of memories from short to long-term storage in the brain causing the hallmark symptom of amnesia. This typically happens when a person’s BAC reaches .14%, almost twice the legal limit in the US.

Blackouts are categorized into two categories based on the severity of amnesia experienced.

• Fragmentary (partial memory loss) blackouts result in partial recollection of events during the drinking period, often recovered when triggered with certain cues.
• En bloc (complete amnesia) blackouts involve total memory loss of events until a person’s BAC lowers and memory processing returns. Events that took place while experiencing an en bloc blackout cannot be recalled.

Both types of blackouts are dangerous and can result in acute and chronic alcohol-related consequences, including:

• Embarrassment
• Public intoxication
• Physical altercations
• Legal consequences
• Driving under the influence (DUI)
• Risky sexual behaviors resulting in STDs or pregnancy
• Sexual assault

The study highlights that blacking out triples a person’s risk for experiencing an alcohol-related consequence. They also concluded that experiencing frequent AIBs was an indicator that a person is at a higher risk of experiencing an alcohol use disorder.

Highlighting The Need For Preventative Measures

Blacking out can place a person in a dangerous situation, but thankfully there are steps that can be taken to lessen the risk.

In their discussion section, the researchers emphasize that their findings support the need for AIB prevention efforts. Since the study focused on college students, recommendations included avoiding participating in drinking games (which helps slow down alcohol intake) and drinking alcoholic and non-alcoholic beverages interchangeably.

Get Help For Alcohol Misuse

If you experience frequent alcohol-induced blackouts or feel as though your alcohol use is problematic, it may be time to seek professional help. Contact a treatment provider to learn about available rehab options and take the first steps toward a healthier, sober future.