(CNN) - Here's a health warning for teens who smoke pot, it could cause lifelong brain damage.
That’s according to a new study published Wednesday in the American Journal of Psychiatry.
Researchers tested the memory and reasoning of 3,826 teens.
According to the report, researchers promised the teens that parents and teachers would not have access to the information. Researchers say they did this to get a more honest account of their marijuana and alcohol consumption.
They found marijuana affected teens' long-term cognitive abilities more than alcohol. Not only that but even when students stopped smoking pot, their memory didn't get better.
Scientists say they need to do more research to find out how and why the brain is affected by early marijuana use.
Smoking weed is still illegal in most of the U.S., but nine states have legalized recreational marijuana use for adults over 21.