I had a roommate in college who we always threw our car keys to at the end of the night when we’d spent the night drinking at a local bar. We were in upstate New York, buried in snow from October through April. My roommate had lived in upstate New York all her life, and she knew how to drive in blizzard conditions. So we trusted her with our lives.
Then one morning early in our sophomore year, I asked her how the heck she had managed to drive us back to campus through the white-out conditions the night before. Her reply was “I drove home?” That’s when I realized she had experienced a black-out, or loss of memory due to heavy drinking. When we talked about it, she told me blackouts during drinking had happened to her a few times before.
I never gave her my car keys again.
Heavy drinking can cause blackouts, and they are more common among adolescents and social drinkers than people used to think. Aaron White, PhD, who is now at NIAAA, and his former colleagues surveyed 772 college graduates on whether or not they had experienced a blackout.
Of the students who had drunk alcohol, 51% reported blacking out at some point in their lives, and 40% experienced a blackout in the year before the survey.
Students said they later learned they’d done things they didn’t remember during a blackout – including stealing, unprotected sex and driving.
What's the science behind this?
Alcohol primarily interferes with the ability to form new long–term memories, and the ability to keep new information active in memory for brief periods, explains White. As the amount of alcohol consumed increases, so does the magnitude of the memory impairments.
Large amounts of alcohol, particularly if consumed rapidly, can produce partial or complete blackouts, which are periods of memory loss for events that transpired while a person was drinking.
Blackouts come from disruption of activity in the hippocampus, a brain region that plays a central role in the formation of new memories.
Yes it's very scary.