If you’ve smoked marijuana before, you may have experienced the sensation of not being able to remember the right words or forgetting what you’re talking about before you get to the end of it. And while this phenomenon has become a staple in the culture of cannabis comedy, a new study by scientists in Switzerland and the U.S. suggests that it might be indicative of something a bit more serious than simply fodder for a joke about stoners.
The study, published today in the journal JAMA Internal Medicine, claims that regular marijuana use may contribute to a noticeable decline in verbal memory skills, especially in middle-aged users.
Researchers working on the project used data from the Coronary Artery Risk Development in Young Adults (CARDIA) study, which compiled a variety of health and wellness data from 5,115 people over the course of 25 years.
Those participating in the original CARDIA study were monitored throughout adulthood, beginning from the time they were between 18 and 30 years old and ending when they were somewhere between 43 and 55.
The most recent research project analyzed the changes in CARDIA participants’ cognitive skills over time and compared those changes to participants’ marijuana use.
They found that while 84.3% of participants reported using marijuana at some point in the past, only 11.6% of them continued regular use into middle age.
Researchers found that the 11.6% who continued using cannabis regularly as they grew older, tended to perform worse in tests associated with verbal memory than did their counterparts.
“Current use of marijuana was associated with worse verbal memory and processing speed,” researchers wrote.
“After excluding current users and adjusting for potential confounders, cumulative lifetime exposure to marijuana remained significantly associated with worse verbal memory.”
The data analyses conducted by researchers ultimately led them to conclude that “past exposure to marijuana is associated with worse verbal memory but does not appear to affect other domains of cognitive function.”