Source: Christopher Ingraham, "What happens when you get stoned every single day for five years," Washington Post, 1 Feb 2016.
"If you smoke a lot of weed — like a lot of it — it can potentially do permanent damage to your short-term memory."
"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. "
"Auer and his team measured lifetime marijuana exposure in a fantastic new unit of measurement they call "marijuana-years." Essentially, if you smoke pot every day for a year, that equals one marijuana-year of use. Ditto if you smoke every other day for two years, or once a week for seven years."
"The relationship between marijuana exposure and memory problems was essentially linear. The more pot people smoked, the worse they performed on the memory tests."
"The association between short-term memory declines — potentially permanent ones — and heavy pot use is very real, according to this study, and shouldn't be discounted."