By Anna Dutton
A study carried out by the Universite De Montreal has found that if teenagers delay smoking pot, (or marijuana), until after the age of 17, there may be a less harmful effect on their brains. Studies showed that those who started using the drug before the age of 17 scored worse on some cognitive tests at age 20 than those who started using it later.
The study was carried out in the Universities children’s hospital where 294 teenagers were taken from a sample of 1,037 French-speaking white males from poorer areas. The teenagers filled out questionnaires between the ages of 13-17 and took cognitive tests at ages 13, 14 and 20. Around half (43%) said that they had smoked pot at some point during that time, with most only doing it a few times a year. By the age of 20, 51% said they still used the drug.
Those who started smoking early had a worse working memory and short term memory- the sort of memory used to store phone numbers for example. The cognitive tests involved making associations between words, being asked to remember a list of words or numbers and finally playing a card game that made them gauge whether they would lose or win money.
The individuals who scored poorly in the cognitive tests reported smoking in their early teens. Castellanos-Ryan suggested that the lower results in the verbal tests were because these individuals tended to drop out of school earlier. She then goes on to reinforce this statement by arguing it is the ‘… social mechanism’ of dropping out of school that results in teenagers being unable to further develop their communication skills.
The study also found that ‘…fundamental life-skills necessary for problem-solving and daily adaption’ were also being affected. These results consequently proved the findings of the study. It was then later published on the 29th of December in the Development and Psychopathy Journal, created by Cambridge University Press.
Natalie Castellanos-Ryan, who is the study’s lead author, has cautioned the results by explaining that the findings were only really applicable to verbal-IQ tests or anything that relied on the frontal cortex of the brain, such as learning by trial and error. She further added that the results are not widespread, and that those who started smoking cannabis after age 17 ‘…performed equally as well’ as those who did not use cannabis.
Castellanos-Ryan concluded that the message of the study was to delay marijuana use among adolescents for as long as possible. She wishes to investigate this further with other studies involving teenagers and see if cannabis can affect any other areas of the brain. She continues by saying that prevention is important as the use of the drug has become more common as many think it is a less harmful recreational drug.
In summary, it seems that cannabis use should be put off for as long as possible, but as Castellanos-Ryan says, we need to be realistic because it is unlikely that these findings will influence the behaviour of all teenagers. Therefore, although the study is not completely conclusive, it seems relevant that teenagers try and wait until the age of 17 before trying the drug.