It’s considered a rite of passage among young people—acting out their independence through heavy, episodic drinking. But a new University of Cincinnati study, the first of its kind nationally, shows how binge drinking among adolescents and young adults could damage a still-developing brain.

High-resolution brain scans on a sample of 29 weekend binge drinkers, aged 18 to 25, found that binge-drinking—consuming four or more drinks in one incident for females and five or more drinks for males—was linked to thinning of the brain matter related to executive functioning (tasks such as paying attention, planning, making decisions, processing emotions, and controlling impulses).

The findings affect a significant population. According to the National Institute on Drug Abuse, 42 percent of Americans between 18 and 25 have engaged in binge drinking.