Teenagers who smoke marijuana regularly achieve poorer grades at school and risk their chances of going to university, according to a major new scientific study.
A longitudinal study of more than 26,400 pupils in Canada found those who started using marijuana at least once a month were around half as likely to achieve high grades as they were before taking up the habit, and were ultimately less likely to pursue university ambitions.
Marijuana users were also four times more likely to skip classes and two-to-four times less likely to complete their homework and value getting good grades.
The findings, published in the Journal of School Health, echo those of numerous earlier studies warning of the drug’s negative effects on attention span and memory, which can in turn cause students’ learning to suffer.
Evidence is mixed however, with one recent report from University College London suggesting higher achievers are twice as likely to smoke cannabis during their teenage years due to their curious minds.
For this latest study, researchers at the University of Waterloo in Canada compared data from 26,475 grade 9-12 school pupils questioned on the highest level of education they would like and expect to achieve.
The results indicated that when students started smoking marijuana daily, their likelihood of reporting ambitions to pursue places at university – rather than stopping at high school level or sooner – was around 50 per cent lower than when the same students had never used the drug.
“The findings support the importance of preventing and delaying the initiation of marijuana use among adolescents,“ said Scott Leatherdale, a professor in the School of Public Health and Health Systems and head of COMPASS, the largest longitudinal study of substance use among young people.
“More youth today use marijuana than cigarettes, yet public health prevention efforts lag behind those of alcohol and tobacco.”
A previous study by the same university suggests a very similar number of teenagers in Canada smoke cannabis as they do tobacco.
Where cannabis is and isn't legal
Where cannabis is and isn't legal
Having been reclassified in 2009 from a Class C to a Class B drug, cannabis is now the most used illegal drug within the United Kingdom. The UK is also, however, the only country where Sativex – a prescribed drug that helps to combat muscle spasms in multiple sclerosis and contains some ingredients that are also found in cannabis - is licensed as a treatment
2/12 North Korea
Although many people believe the consumption of cannabis in North Korea to be legal, the official law regarding the drug has never been made entirely clear whilst under Kim Jong Un’s regime. However, it is said that the North Korean leader himself has openly said that he does not consider cannabis to be a drug and his regime doesn’t take any issue with the consumption or sale of the drug
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In the Netherlands smoking cannabis is legal, given that it is smoked within the designated ‘smoking areas’ and you don’t possess more than 5 grams for personal use. It is also legal to sell the substance, but only in specified coffee shops
Although in some states of America cannabis has now been legalised, prior to the legalisation, police in the U.S. could make a marijuana-related arrest every 42 seconds, according to US News and World Report. The country also used to spend around $3.6 billion a year enforcing marijuana law, the American Civil Liberties Union notes
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Despite cannabis being officially illegal in Spain, the European hotspot has recently started to be branded, ‘the new Amsterdam’. This is because across Spain there are over 700 ‘Cannabis Clubs’ – these are considered legal venues to consume cannabis in because the consumption of the drug is in private, and not in public. These figures have risen dramatically in the last three years – in 2010 there were just 40 Cannabis Clubs in the whole of Spain. Recent figures also show that in Catalonia alone there are 165,000 registered members of cannabis clubs – this amounts to over 5 million euros (£4 million) in revenue each month
In December 2013, the House of Representatives and Senate passed a bill legalizing and regulating the production and sale of the drug. But the president has since postponed the legalization of cannabis until to 2015 and when it is made legal, it will be the authorities who will grow the cannabis that can be sold legally. Buyers must be 18 or older, residents of Uruguay, and must register with the authorities
Despite the fact that laws prohibiting the sale and misuse of cannabis exist and is considered a habit only entertained by lower-income groups, it is very rarely enforced. The occasional use of cannabis in community gatherings is broadly tolerated as a centuries old custom. The open use of cannabis by Sufis and Hindus as a means to induce euphoria has never been challenged by the state. Further, large tracts of cannabis grow unchecked in the wild
In 2001, Portugal became the first country in the world to decriminalize the use of all drugs, and started treating drug users as sick people, instead of criminals. However, you can still be arrested or assigned mandatory rehab if you are caught several times in possession of drugs
9/12 Puerto Rico
Although the use of cannabis is currently illegal, it is said that Puerto Rico are in the process of decriminalising it
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The US state became the first in the country to legalise marijuana in January 2014. In February 2015, President Obama recently said he expects to see more states "looking into" legalisation. However, it is illegally to grow more than six cannabis plants and to possess more than 28 grams of the drug
Oaksterdam in Oakland, California, is the world's only university dedicated to the study and cultivation of cannabis. If you are court in California with anything up to an ounce of cannabis, you will be fine $100, but you will not get a criminal record, nor will you have to appear in court
Cannabis is grown in the wild and has been used to treat conditions such as gout and malaria. But, officially the substance is illegal to consume, possess and sell
Karen Patte, a post-doctoral fellow and lead author of the paper, added that researchers had found a reduction in the number of young people perceiving marijuana to be harmful.
“Yet they have greater vulnerability to adverse consequences,” she said.
“We found that the more frequently students started using the drug, the greater their risk of poor school performance and engagement.”
The study also looked at the effects of alcohol use on academic aspirations and expectations.
Unlike marijuana, students partaking in regular alcohol use tended to report goals to pursue post-secondary education.
“Drinking has long been tied to university settings, which may make alcohol a more acceptable substance choice for students planning to attend university,” said Mr Leatherdale.
If the Cannabis Act is passed, the nation would become the second in the world after Uruguay to regulate a legal marijuana market.
Mr Leatherdale said: “All substances present risks to health and well-being. With marijuana legalisation on the horizon, it’s critical we understand these risks in order to promote successful transitions into adulthood for our youth.”Reuse content