Photo: Chris Young-Archives The canadian Press
In Canada, more than 20 % of young people between 15 and 25 years consume cannabis on a daily or occasional basis.
The state of depression and thoughts of some young canadian adults would not be unrelated to their cannabis use during the teenage years, according to a new study published Wednesday in the medical journal JAMA Psychiatry.
“It has been estimated that in Canada, 7 % of the diagnoses of depression in young adults 18 to 30 year olds are related to cannabis. It does not seem as large in percentage, but in number it is almost 25 000 young people concerned “, drops the phone to Dr. Gabriella Gobbi, a researcher and psychiatrist at the research Institute of the McGill university health Centre (RI-MUHC), who led the study.
It is the first meta-analysis on the subject, fruit of the collaboration of the ri MUHC, McGill University and researchers in the us and the uk. If a number of studies have already focused on the link between cannabis and risk of psychosis, early school leaving and cognitive problems in adolescents, few of them are interested in the role of this drug in cases of depression, anxiety, suicidal thoughts or suicide attempts, once arrived at adult age.
Cannabis use in adolescence would therefore lead to an increased risk of developing major depression in early adulthood, and suicidal tendencies, according to this analysis. The results have not been significant to the link with anxiety.
In all, more than 3000 studies have been reviewed, of which ten only were finally chosen, analyzing the whole journey of 23 317 individuals. “We had very strict criteria. We took essentially the longitudinal studies and prospective studies, those who studied children from the age of 4 years up to 32 years, and it was necessary that [the latter] do not show any signs of depression, anxiety, or suicidal thoughts before you begin to consume cannabis, ” says dr. Gobbi.
For its part, the neuropsychologist Dave Ellemberg — which has not participated to the research published in JAMA Psychiatry — also notes the close relationship between cannabis use and depression among these patients.
In nearly 20 years of practice, a lot of people aged 25 to 35 years came into his office depressed and wondering if their past consumption of cannabis did not had an irreversible impact on their brain and their functioning in daily life.
“They have the impression that their brain does not work as well as it should be : memory loss, difficulty to organize, or to ignore the elements of distraction, lack of motivation… They no longer recognise themselves, and feel they have mortgaged their brain functions “, note that who is also director of the clinical neuropsychological assessment and learning disorders of Montreal.
Worrying to stay in this state for the rest of their life, some have come to question the usefulness of continuing to live, ” he said Ellemberg.
“It is all the more worrying in the context of legalization in which we are,” says the researcher. The legalization comes to trivialize the effects of cannabis and people are poorly informed about the long-term consequences of daily use. “
Dr. Gobbi abounds in the same direction, and even speaks of a ” public health problem “. It is particularly noted that the real impact of cannabis may be under-estimated by some studies that date back several years. The level of THC found in the cannabis has increased significantly in recent years. “A joint in the 1960s, it was 6 % THC. Today, it is 10, 20, or even 30 % THC in a single joint, even on the legal market “, she noted.
Public policy should address, she believes. “If fewer adolescents were using marijuana, there would be less cases of depression [in the company]. “
She reminds us that in Canada, over 20 % of young people between 15 and 25 years consume cannabis on a daily or occasional basis. They represent the age group that uses the most within the population.
And stick to a law that prohibited smoking before the age of 18 or 21 years of age — as is the wish of the government of Quebec — do not change the proportion of young people who use cannabis, in his opinion.
Prevention is the key. It is better to educate teens so that they learn to resist peer pressure on drug use. Invest in the sport, the middle school and the support of parents has also proven itself — including Iceland — in the area of prevention of consumption of drugs, ” says Ms. Gobbi.