Binge as well as social drinking can lead to blackouts
By Nicole Arulanantham
March 28, 2011 1:23 a.m.
A UCLA student woke up at 6 a.m. after a long night of drinking to discover drawings all over his body. Puzzled, he made it to his 9 a.m. class with artwork still on him and no recollection of how it had gotten there.
“I was at a party, and everyone was drinking. It was like a competition,” said the student, who wishes to remain anonymous.
“The last thing I remember is dancing on top of a table.”
A drinker cannot recall the events of a previous night when alcohol prevents the brain from converting short-term memory to long-term memory, said Igor Spigelman, a UCLA professor of oral biology and medicine who researches the effects of alcohol on the brain.
This inability to form long-term memory is known as a blackout ““ a common experience on college campuses, Spigelman said.
There are two types of alcohol-induced blackouts, he said. The first, known as a partial blackout, is more common and causes the brain to convert short term memory to contextual memory.
When this occurs, a person will be only be able to remember an event if prompted with the details. This kind of blackout can occur during binge drinking as well as social drinking, he said.
Binge drinking is defined as the consumption of four or five alcoholic drinks in a period of two hours, according to the Centers for Disease Control and Prevention website. Social drinking implies alcohol is consumed more slowly, Spigelman said.
“You may forget meeting a person or you won’t remember their name. You may remember going to the party but not specific details,” Spigelman said.
The second type of blackout is called a full blackout, after which a person won’t remember anything that happened while intoxicated.
This is a rare occurrence and requires a person to consume much more alcohol than would lead to a partial blackout.
Gender and genetic dispositions are two factors that determine a person’s chances of experiencing a blackout, Spigelman said. Women are more susceptible, and different ethnicities may have different tolerances as well. For example, there is an enzyme found in people of Asian descent that causes the digestive system to metabolize alcohol slower, causing a red flush known as the Asian glow, he said.
The rate and amount of consumption also determine whether a person will blackout, Spigelman said. Typical college drinking traditions are set up so the drinker takes in far more alcohol than necessary to become inebriated, thus increasing the chance of a blackout.
“The chance of longer and larger blackouts is greater when people drank alcohol really quickly,” Spigelman said. “Those who spread out consumption reported fewer blackouts.”
Additionally, people who drink on a full stomach are less likely to blackout than those who drink on an empty stomach. Food in the digestive system will slow down absorption of alcohol, leaving the drinker with lower blood alcohol levels than someone who hasn’t eaten beforehand.
The hippocampus, which is a region of the brain responsible for converting short- to long-term memory, may take months to change events to memories that a person can recollect years later, Spigelman said. Frequent inhibition of this process can cause brain damage. People with alcohol dependency and no other unrelated medical conditions have been found to have a decreased brain size, he said.
Consuming alcohol to the point of experiencing a blackout also releases excessive amounts of the excitatory neurotransmitter glutamate into the brain, said Kelly Courtney, a doctoral student in clinical psychology at UCLA.
High glutamate levels cause cell death, which has an immediate effect on brain functionality. The most obvious impact is seen in the brain’s frontal lobes, which play a role in preserving working memory and facilitating high-level functioning.
“Basically any type of frontal lobe process has been shown to be impaired by alcohol use,” Courtney said.
She added that it is unclear whether this damage is caused more by drinking large amounts of alcohol over short periods of time or by drinking moderate amounts daily over an extended period of time.
The UCLA student did not realize he had blacked out. He remembered having 26 drinks and thought he had passed out after dancing on a table. It was only when friends filled him in that he realized his antics hadn’t stopped there.
“It was like putting together a puzzle,” he said. “I would hear parts (of what I did) from other people and had to try and figure out what happened myself.”
