Allegations that U.S. Supreme Court nominee Brett Kavanaugh sexually assaulted Christine Blasey Ford when the two were teenagers have not just prompted uncertainty about Kavanaugh's confirmation, they also have prompted discussion about intoxication, sexual assault and how alcohol impacts memory—especially in the developing teenage brain.
The contentious topic typically arises in discussions of college sexual assault—like the case of Brock Turner, a 19-year-old convicted for sexually assaulting a young woman who had passed out from drinking. Lawyers of the accused often use the victim's intoxication to cast doubt on their recollection of events, while advocates argue it's an unfair standard, as both parties are often impaired. Research shows that in about half of all sexual assaults on campus, either the victim, the perpetrator or both were consuming alcohol.
Science, meanwhile, is becoming clearer on the issue of alcohol and the brain. Depending on the amount and frequency of consumption, alcohol can affect both short- and long-term memories, especially in young, developing brains.
"Enough of the facts are in from neurobiological research to understand that alcohol has a substantial impact on the brain's ability to transfer information into long-term memory," wrote Jamie Smolen, an associate professor of medicine at the University of Florida, in an article for the website The Conversation.
In the case of Kavanaugh's alleged assault, it's uncertain how much he or Ford was drinking that night.
Ford, now a professor at Palo Alto University, accused Kavanaugh of assaulting her at a high school party more than 30 years ago. In an interview with The Washington Post, she said he pinned her on a bed, groped her, drunkenly trying to pull off her bathing suit, and covered her mouth to keep her from screaming. She said most people at the party had one beer while Kavanaugh was heavily intoxicated.
Kavanaugh has categorically denied the allegation, saying "I did not do this back in high school or at any time." He has not commented on his level of intoxication. In past speeches, he has alluded to heavy drinking as a student.
According to the National Institute on Alcohol Abuse and Alcoholism, alcohol can produce detectable impairments in memory after only a few drinks. As the amount of alcohol increases, so does the degree of impairment.
The greatest dangers come from binge drinking, generally defined as consuming several drinks—four for women, five for men—within two hours and elevating the blood alcohol level to 0.08 or higher. It leads to the deaths of about 1,825 people between the ages of 18 and 24 each year, and is associated with about 97,000 sexual assaults.
Binge drinking can lead to blackouts—an interval of time for which the intoxicated person can't recall key details of events, or even entire events. It's the result of alcohol interfering with a process called encoding by which the brain transfers memories from short term to long term.
But alcohol can cause people to forget more than just one event. Research suggests binge drinking causes neurodegeneration in regions of the brain responsible for learning and memory, leading to long-term deficits.
In one study, researchers recorded structural changes in the brains of rodents given alcohol during adolescence. By the time the rodents reached adulthood, the nerve cells in their hippocampus—the area of the brain linked with learning and memory—were abnormally shaped.
Research in humans has found young binge drinkers experience a depletion of glutathione, an antioxidant that protects the brain from free radicals. When glutathione is depleted in the hippocampus, there is less of a protective effect, and that persists even after someone stops drinking.
Alcohol also affects the development of white and gray matter in the brain. White matter allows signals to travel quickly across the brain while gray matter is involved in processing information. Repeated alcohol consumption can decrease the amount of white matter in the brain and hurt a portion of gray matter in the prefrontal cortex, which controls executive functions like attention, concentration, self-control and decision-making.
"The consequences can be embarrassing," Smolen wrote for The Conversation, "and worse, can include injuries, sexual assault, unsafe sex, drunk driving and police involvement after drinking."
While women are more vulnerable than men to many of the medical consequences of alcohol use—like damage to the liver and heart—research has been inconclusive in finding gender differences when it comes to brain damage.