People who smoke marijuana over time may have trouble remembering words on a list by the time they reach middle age, suggests a new study.
The study found long-term use of weed could impact “verbal memory,” or the part of the brain that helps you memorize words or language. However, it did not report impact on other cognitive functions, such as the ability to think quickly, focus or problem-solve, reports CBS News.
“This study is timely because marijuana use has increased, and many states have legalized marijuana use or decriminalized its possession,” Deborah Levine, who was part of the research team, said in a statement. “We need to better understand the risks of marijuana use, particularly its effects on brain health, to inform decision making by teenagers and adults as well as policymakers.”
The study’s co-author, Reto Auer, who is an academic chief resident at the University of Lausanne, in Switzerland, told CBS News that they were surprised by the findings. Marijuana’s impact on the ability to memorize words appeared to be incremental, which means that “the more you smoke, the lower your verbal memory,” said Auer . He stressed that the results were “only associations,” and not proof of cause and effect.
Researchers studied men and woman over a span of 25 years starting when they were young adults. Their findings were published in JAMA Internal Medicine.