Smoking weed as a teen might change your life for the worse — UC San Diego study

Researchers at UC San Diego have confirmed something that has long been suspected anecdotally: Those stoned kids in high school just don’t keep up.

According to a recently released study involving more than 11,000 teens who were tracked from the age of 9-10 until they were 16-17, “cannabis use [is] tied to slower gains in memory, focus and thinking speed, as well as worse memory over time during key years of brain development.”

Studies of illegal drug use are always complicated by ethical concerns, of course — researchers can’t provide the substances to those being researched — so the scientists instead allowed the children to self-report their marijuana use. That data was augmented with biological testing, including hair, urine and saliva samples, from which researchers can determine cannabis use going back several months.

The study focuses on youth cannabis consumption because “Adolescence is a critical time for brain development,” according to Natasha Wade, who is an assistant professor of psychiatry at UC San Diego School of Medicine and the lead author of the study.

“… what we’re seeing is that teens who start using cannabis aren’t improving at the same rate as their peers,” Wade said in a news release issued this week. “These differences may seem small at first, but they can add up in ways that affect learning, memory and everyday functioning.”

What the UCSD scientists found in their study was evidence that in a wide swath of skills, including thinking speed, the ability to focus and memory, teens who got high displayed noticeably less growth over time versus their straight peers, with the advances made by the children consuming cannabis leveling off as opposed to their counterparts, whose abilities improved over time.

While the differences between the stoned students and their peers might not seem significant, they might have outsize results.

“[This] is a really significant time in life where they’re put to the test a lot, and it’s a very competitive environment for teens right now, and so we’re seeing that, you know, maybe it’s like the equivalent of a half a grade in some areas in school, and that might not make a huge difference to their lives, but it might also put them on different trajectories in their life to kind of reach their own personal goals,” Wade told NBC 7 on Tuesday.

Wade said the most surprising element of the study was the regularity in the results.

“… the data are really consistent across all the different cognitive domains, all the different types of thinking abilities we assessed,” Wade said.

Wade said that, if people do consume cannabis, they should wait till they grow up.

“Delaying cannabis use supports healthy brain development,” Wade said. “As cannabis becomes more widely available, it’s important for families and teens to understand how it may affect the developing brain.”

The researchers’ plan for now is to continue tracking the development of all the children who participated in the study into adulthood.