Marijuana myth debunked

A new U study concludes that IQ levels are not directly affected by cannabis usage.

University of Minnesota student Levi smokes pot from a bong at his home in the Southeast Como neighborhood on Tuesday.

Sam Harper

University of Minnesota student Levi smokes pot from a bong at his home in the Southeast Como neighborhood on Tuesday.

Raj Chaduvula

Dope doesn’t necessarily make you dopey, according to a University of Minnesota study published this month.
 
 
The eight-year study measured the IQs of twins — some of whom abstained from marijuana, while others reported using the drug — over time to determine how marijuana usage affected intelligence. Researchers concluded that measured drops in IQ were likely not directly caused by drug use but instead by common factors affecting both twins.  
 
 
“It’s not the marijuana that is causing the decline,” said Joshua Isen, a psychology postdoctoral research associate from the University of Minnesota who co-authored the study.
 
 
Participants in California and Minnesota were measured during pre-adolescence at ages 9-12 and in adolescence at ages 17-20. 
 
 
Working with twins allowed researchers to control as many factors as possible, Isen said, like genetics and upbringing. 
 
 
Despite the notion that marijuana usage during adolescence can negatively affect neurocognition, genetic and shared environmental factors showed a greater observable decrease in IQ for both twins, he said. 
 
 
Levi, a junior majoring in computer science, has been a recreational marijuana smoker since his freshman year of college. Levi asked to be identified only by his first name.
 
 
He said he considers himself a responsible user and wasn’t surprised when he heard about the research’s results. Levi said he doesn’t feel that marijuana directly affects his intellectual capacity but rather allows him to relax in his leisure time or in social situations.
 
 
“It’s like drinking — you get done with your work and then you drink. Same thing for smoking marijuana,” he said. 
 
 
Paul Armentano, deputy director for the National Organization for the Reform of Marijuana Laws, said the legalization of marijuana can help thousands of young people who use responsibly avoid punishments ranging from jail sentences to loss of welfare eligibility.
 
 
“Minor marijuana possession offenders … should not be saddled with a criminal record and the lifelong penalties and stigma associated with it,” Armentano said. 
 
 
Armentano said he thinks studies like the University’s recent one could help advocates pushing for the drug’s legalization for recreational use.
 
 
“The study’s conclusions are consistent with those of previous, well-controlled trials finding that cannabis exposure possesses little if any neurotoxicity risk,” he said.