Kavanaugh allegations raise questions about alcohol, sexual assault, and the reliability of memory

Allegations that U.S. Supreme Court nominee Brett Kavanaugh sexually assaulted Christine Blasey Ford when the two were teenagers have not only prompted uncertainty about Kavanaugh's confirmation but have also rekindled the debate around 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 of 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 the recollection of events, while advocates argue it's an unfair standard, as both parties are often impaired. Research shows that in about half of sexual assault cases on campus, 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 memory, 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 were 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 to a bed, groped her, drunkenly tried 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 percent 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 assault cases.

It's a significant issue of concern with teens, said Jessica Barson, an assistant professor in the department of neurobiology and anatomy at Drexel University College of Medicine. "Teens are not drinking as frequently as adults," she said. "But when they do, it's a lot more. So almost all their drinking is binge drinking."

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, through 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.

"Someone who is drinking a lot in their teen years might not have great memories of that period of life," Barson said. But more research is needed on the topic, she said. Currently, there is more evidence of the effects of alcohol on the prefrontal cortex — an area of the brain that controls executive functions like attention, concentration, self-control and decision-making — than its effects on the hippocampus.

Since the prefrontal cortex is still developing in the late teens and early 20s, that is the region most disrupted by alcohol use, Barson said. Repeated alcohol consumption can decrease the amount of white matter in the brain, which allows signals to travel quickly, and hurt a portion of gray matter in the prefrontal cortex, which is involved in processing information. It can lead people to become more impulsive, she said.

"The consequences can be embarrassing, and worse, can include injuries, sexual assault, unsafe sex, drunk driving and police involvement after drinking," Smolen wrote for the Conversation.

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. Female brains develop slightly earlier than male brains, Barson said, but there's not enough research to know how that might impact the effect of alcohol on their memories or executive function.