Many have heard that smoking marijuana makes you stupid – at least that’s the image that’s often portrayed by the media. A new study released by JAMA Internal Medicine shows that indeed smoking marijuana can cause permanent damage to your short-term memory – however to experience these effects one must smoke daily for several years.
“The study found that people who smoked marijuana on a daily basis for a long period of time – five years or more – had poorer verbal memory in middle age than people who didn’t’ smoke, or who smoked less … The relationship between marijuana exposure and memory problems was essentially linear. The more people smoked, the worse they performed on the memory tests. But just how much worse?
To understand how memory was impacted, participants were asked to remember a series of words. The performance of regular marijuana smokers was compared to those who smoke less frequently or not at all.
“Let’s say we have two groups of 10 people each. You tell each of them a list of 15 words and ask them to memorize them. Then 25 minutes later, you ask them to recall all the words to the best of their ability.
The first group consists of 10 people who don’t smoke marijuna or only do so occasionally. Let’s say on average, people in this group would be able to remember nine out of the 15 words. The second group consists of people who smoked pot every single day over a period of five years. On average, they’d be able to recall 8.5 out of the 15 words.
That doesn’t seem like a huge cognitive difference, and by and large it’s not.”
Read the full study, published in the journal JAMA Internal Medicine, and titled “Association Between Lifetime Marijuana Use and Cognitive Function in Middle Age”.