Article by Brandon Specktor, Live Science
Which came first, the burnout or the weed?
Though various studies have linked teenage cannabis use to noticeable cognitive decline in adulthood, a recent paper published in the journal NeuroImage casts doubt on the existence of this straightforward cause-and-effect relationship.
Among a sample of 28-year-olds who took a working-memory test while undergoing an MRI brain scan, individuals who started smoking marijuana in adolescence performed just as well or even better than individuals who never smoked cannabis, the study found. What’s more, the brain regions that worked more slowly in the cannabis-smoking set compared to the nonsmokers were inconsistent from person to person, suggesting that other factors besides marijuana could account for the cognitive difference. [7 Ways Marijuana May Affect The Brain]
“We know that adolescent brains are still changing and developing, and we also know that this is a time when a lot of people are experimenting with cannabis and other drugs,” said lead study author Brenden Tervo-Clemmens, a doctoral student in clinical psychology at the University of Pittsburgh. “I’m interested in this cause-and-effect relationship that may or may not exist.”
Marijuana and the brain
Tervo-Clemmens and his colleagues recruited 75 participants from the Maternal Health Practices and Child Development (MHPCD) project — a longitudinal study that looks at the effects of prenatal drug exposure on children from low-income families — to take a working-memory test while undergoing a brain scan. All of the participants’ substance use experience had been closely monitored for their entire lives, Tervo-Clemmens said.
The researchers focused on how old the participants were when they started smoking marijuana and how often they used the drug. Among the 60 participants who said they had tried marijuana, 46 reported repeated use (the other 14 said they tried it once and then quit) and started smoking at an average age of 15 years old.