Marijuana. (AP Photo/Ed Andrieski, File)

Here it is. Science: Smoking weed all the time does not appear to help your academic performance at college. It appears it may hurt it.

A study following college students over years to measure the impact of marijuana use found those who smoked it often were more likely to skip class, get worse grades, and take longer to graduate.

As marijuana becomes increasingly available and acceptable – almost 60 percent of adults now favor making it legal nationwide, according to a recent Gallup survey —  a researcher warns that parents and educators should be worried about the drug’s effect on even high-functioning college students, those who go on to graduate.

[Marijuana law creates confusion but finds growing acceptance in the District]

“This is a very under-recognized and under-discussed consequence of marijuana use that we’re concerned about,” said Amelia Arria, an associate professor and the director of the Center on Young Adult Health and Development at the University of Maryland School of Public Health. “There has been a general acceptance of the notion that marijuana is a benign drug.

“From our perspective — from the perspective of researchers who are … focused on the academic achievement outcomes associated with marijuana use — that is squarely at odds with the” evidence, including grades as reported by registrars, she said.

Researchers followed more than 1,000 college students, with a model that takes into account other factors that could put students at greater risk or help them, such as alcohol use and psychological functioning.During freshman year, those who used marijuana more often tended to skip more classes, get worse grades and take longer to graduate. As marijuana use became more frequent, grades tended to drop, they found, and as it declined grades tended to bounce back.

Campus clinicians would hardly be surprised by this, Arria said. And there’s a stereotype of a regular user that people laugh about, she said, the checked-out, sort of dopey persona. “But I think parents should be very concerned. … It’s a very real consequence.”

Paul Armentano, the deputy director of NORML, which advocates for legal adult marijuana use, questioned the findings. It should hardly be a surprise, he said, that students who most often skip class are less likely to do well academically. But correlation does not imply causation, he said, and lots of things could cause a student to miss lots of classes — such as playing for a Division I team.

“Absent a cause-and-effect relationship, it would then appear that other common lifestyle-related variables, such as person’s willingness to engage in rebellious or anti-authority activity, are a better predictor of class attendance rather than one’s use of cannabis.”

Arria counters that this was a longitudinal study that measured and adjusted for factors such as rebelliousness. For anyone who knows someone who uses marijuana, she said, “I think these findings would not be surprising.”


Read more:

Is legal marijuana smoke in D.C. affecting the children of users?

Marijuana in Alaska has long been legal

D.C. smells like marijuana, and residents don’t really care