Recreational marijuana has been legalized in two states and cleared for medicinal use in several more, but new research suggests the drug isn’t quite as benign as its proponents claim.

According to research from Northwestern University, young adults who smoke pot as infrequently as once or twice a week also have significant brain abnormalities.

The two regions most impacted by marijuana were the nucleus accumbens and the amygdala, parts of the brain most responsible for decision-making, motivation and processing emotions.

“For the NAC, all three measures were abnormal, and they were abnormal in a dose-dependent way, meaning the changes were greater with the amount of marijuana used,” says Dr. Hans Breiter, one of the study’s authors. “The amygdala had abnormalities for shape and density, and only volume correlated with use. But if you looked at all three types of measures, it showed the relationships between them were quite abnormal in the marijuana users, compared to the normal controls.” (Fox News)

Paul Asay has covered religion for The Washington Post, Christianity Today, Beliefnet.com and The (Colorado Springs) Gazette. He writes about culture for Plugged In and wrote the Batman book God on the Streets of Gotham (Tyndale). He lives in Colorado Springs with wife, Wendy, and his two children. Follow him on Twitter.