Friday, December 11, 2009
Blacked-out drinkers might not remember whom they were with, what they said or what they did, leading to embarrassing, if not dangerous, situations.
Psychology Professor Kim Fromme’s lab is one of the few in the country to research blackouts. She studies drinking among college students.
I interviewed Fromme for an article about alcoholism and addiction research at the university. That article focused on another part of her research. Here’s some of what her lab has learned about blackouts.
Fifty percent of people who drink enough alcohol to reach a blood alcohol content (BAC) of 0.06 percent or greater have blackouts, but most blackouts occur when BAC reaches 0.20 percent or greater. The legal limit is 0.08 percent.
For the studies, she recruits people who have had blackouts in the past and people who have not. Some of the research includes alcohol administration (drinking) in Fromme’s Bar Lab, but not to the point of blacking out.
The blackout studies show some people are more vulnerable to experiencing blackouts than others when they drink too much.
“We’ve found that people who do and do not experience blackouts don’t differ on memory processes when sober,” she said. “It’s only when alcohol is introduced that they differ, which is pretty interesting.”
One of Fromme’s doctoral students, Reagan Wetherill, has run alcohol administration studies to examine the memory processes of those who experience blackouts.
In one study, Wetherill used functional Magnetic Resonance Imaging (fMRI) brain scans. The participants, people had experienced blackouts and those who hadn’t, were tested twice, once sober and once intoxicated to a target BAC of 0.08 percent.
Wetherill’s findings helped identify the neural structures in the brain that are different between people who do and do not have alcohol-induced blackouts.
Fromme said that future blackout research in her lab probably will address the question of whether alcohol is unique in its capacity to affect memory in people who have experienced blackouts.
“The key question about blackouts, for me,” she said, “is whether alcohol intoxication uniquely causes the memory deficits we see when those who have previously experienced blackouts are intoxicated – or whether they would show the same memory impairments if you decreased their cognitive processes in another way, say with a divided attention task.
“Given the resources, I would like to attempt to replicate our findings about memory deficits (in those who previously experienced blackouts) using a different cognitive load, and compare those findings to those for alcohol intoxication.”