Study: Throwing a jar to improve the learning of adolescents: shots

Marijuana, it seems, is not a performance enhancing drug. That is, at least not in the young and not when the activity learns.

A study published Tuesday in the Journal of Clinical Psychiatry finds that when teens stop using marijuana – even for a week – their verbal learning and memory improves. The study helps to provide more and more evidence that marijuana use among adolescents is associated with a reduction in neurocognitive functioning.

According to a National Institutes of Health survey conducted in 2017, more than 14% of high school and college students reported using marijuana in the last month. According to the US Department of Health, marijuana use has increased among high school students over the past decade. & Personal services.

At the same time, the percentage of teenagers who think that regular marijuana use poses a major risk to their health has declined sharply since the mid-2000s. Moreover, the legalization of marijuana can affect how which young people think of drugs. One study noted that after 2012, when marijuana was legalized in the state of Washington, the number of grade eight students who thought marijuana posed health risks declined by 14%.

Researchers are particularly concerned about the use of marijuana in young people because THC, the active ingredient in marijuana, specifically affects those parts of the brain that develop during the first six months of life. adolescence.

"The adolescent brain is experiencing significant neurological development in the 1920s, and the areas to be developed last are those that are most populated by cannabis receptors and also play a critical role in cognitive functioning," explains Randi Schuster. Schuster is the director of neuropsychology at the Center for Addiction Medicine at Massachusetts General Hospital, and the lead author of the study.

Schuster and the team of researchers have sought to determine whether the cognitive functions potentially affected by marijuana use in adolescents – particularly attention and memory – improve when they get worse. Abstain from using marijuana.

They recruited 88 teenagers and young adults using jars, aged 16 to 25, and some agreed to stop smoking (or otherwise consuming) marijuana for the month.

Schuster says the researchers wanted to recruit a range of participants, not just intensive users or those participating in a treatment program, for example. Some of the youths smoked once a week; some smoked almost every day.

The researchers randomly distributed the volunteers in a group of abstentions and a group of abstentions. They announced the bad news to those who were chosen to refrain at the end of their first visit, and Shuster said that they had it surprisingly well received.

"People were generally good," she says. "We sort of looked at what would look like next month and helped them develop strategies to stay sober."

A motivation for non-players to stay with the program? They received increasing amounts of money each week from their monthly study.

The researchers tested urine from both groups on a weekly basis to ensure that THC levels for the abstinent group were decreasing, but that levels for the control group remained consistent as they continued. use.

Also at each visit, participants performed a variety of tasks that tested their attention and memory with Cambridge's automated battery of neuropsychological tests, a validated cognitive assessment tool.

The researchers found that after four weeks, there was no noticeable difference in the scores of attention between marijuana users and non-users. However, the memory scores of non-users have improved, while the user memory has remained essentially the same.

The verbal memory test challenged participants to learn and remember new words, which allows us to "look at both their ability to learn information from the first presentation of words, as well as the number of words that they are capable of recovering. "term storage memory after a delay," says Schuster.

Verbal memory is particularly relevant for teens and young adults when they are in the classroom, says Schuster.

"For a teenager sitting in his story class who is learning new facts for the first time, we suspect that active cannabis users may have difficulty putting this new information into their long-term memory," he said. said Schuster.

Although this study does not prove that cannabis abstention improves the attention of adolescents, other studies have shown that marijuana users are less successful in the attention tests than non-cannabis users. -users. Schusters assumes that abstinence could take more than four weeks for attention levels to improve.

It is interesting to note that most of the improvement in the memory of the abstinent group occurred during the first week of the study, leaving researchers hopeful.

"We were pleasantly surprised to see that at least some of the deficits we believe to be due to cannabis seem to be reversible, and at least some of them are fast, which is good news." said Schuster.

Krista Lisdahl, associate professor of psychology at the University of Wisconsin Milwaukee, did not participate in the study, but also studies the neuroscience of addiction. For this reason, it is difficult to determine whether memory enhancements have reduced participants to baseline levels prior to marijuana use.

In addition, since the study lasted only four weeks, it is impossible to draw conclusions about the long-term effects of marijuana use among youth, particularly on the direct effect of marijuana on school performance. , sleep or mood.

Lisdahl says that longitudinal studies such as the study on cognitive brain development in NIH teens could provide more information on what marijuana does to teenagers' brains. It could also reveal what will happen if teens stop using marijuana and their brains function optimally.

Lisdahl is participating in the NIH study, which has so far enrolled more than 11,000 children aged 9 and 10 and will follow them into adulthood. It is the largest long-term research study on child brain development in the United States, and it assesses how everything from screen time to concussion to drugs affects adolescent brain.

Meanwhile, Lisdahl explains that the findings of the new study – that marijuana abstinence is associated with improvements in adolescent learning and memory – send a positive message.

"I remain optimistic that we can show the recovery of function with sustained abstinence," she says.

Rachel D. Cohen is an intern at NPR's Science Desk.