A study on teenagers has shown that binge drinking in this age group negatively affects girls more than it does boys, especially in tests on working spatial memory.

The study is a joint endeavor between UC-San Diego and Stanford. It included 95 teenagers ranging in age from 16 to 19, 40 of whom were binge drinkers, and defined “binge drinking” as four or more drinks for a girl or five or more drinks for a boy.

The adolescents were given a series of spatial working memory tests, which they performed in a functional magnetic resonance imaging (fMRI) machine so researchers could examine the cognitive effects of the binge drinking on the brain. Spatial working memory, UC-San Diego graduate student and lead author Lindsay Squeglia explained, is the ability to remember “where things are in space around you.”

UC-San Diego psychiatry professor and co-author Susan Tapert said that the tests the students performed were similar to IQ tests, citing attention-testing tasks like crossing out a specified letter, a “visual constructional task” that involves redrawing a given picture, a puzzle-like task where adolescents would recreate a design shown in a picture with blocks and a “working memory test which examines your ability to manipulate information that you hold in your mind.”

Tapert added that the adolescents were purposefully examined after the initial effects of alcohol disappeared, giving them around three or more days to recuperate.

“What we found was that the kids who were binge drinking have less brain activation when they were doing a spatial working memory test,” Squeglia said. The effect was strongest for the female binge drinkers, so female binge drinkers did much worse than female controls and then for male binge drinkers, they did worse, but it wasn’t as strong of an effect for males.”

Despite the gender discrepancy found by the study, Squeglia said that the results of the study are not unexpected.

“It didn’t [surprise me] actually, because some of the adult literature has shown alcohol more negatively affects females, and so we purposefully were trying to look at the gender in this study to see if that was the same case for adolescent females,” she said.

Squeglia said the difference is correlated with the difference in the male and female brains during adolescence, in that different hormones affect them.

She also mentioned that there is a difference in the “acute effects” of drinking, explaining that more typically female characteristics like lower body weight, slower metabolism and higher body fat content make them more vulnerable to alcohol.

Both Squeglia and Tapert noted that the recently published study is “cross-sectional” in that it examines the students in just one moment of their lives. However, both also added that longitudinal data that followed the studied adolescents over time was being used to make sure that the effects found on both the male and female binge drinkers was a consequence of the alcohol itself.

“The same kids who were in this study, we’re following over time to see if increases in drinking follows with a greater degree of these abnormalities, and the flip side of that is to see if the kids who stopped drinking show improvements in these abnormalities,” Tapert said.

Squeglia added that the study is in its eighth year.

According to Tapert, the study did have its challenges. She explained that they had to be careful with the selection of subjects.

“You can’t put somebody who had braces in the MRI, and a lot of young people have braces,” she said. “There’s also a lot of young people who binge drink who also use a lot of other drugs, and we couldn’t really include them in this study since we’re really trying to just look at the effects of binge drinking in this particular study.”

Squeglia said that she hopes that exposure to the results of the study will discourage teenage binge drinking. She added that parents should talk to their kids about drinking instead of drinking with them to “teach them how to drink.”

“The study that Lindsay [Squeglia] did here is larger than most published fMRI studies, so the results are fairly robust, and I think it gives us a reason to be concerned for teenage girls who are drinking four or more drinks in an occasion,” Tapert said.