Teens who start using cannabis before age 15 are more likely to use the drug frequently later in life. They are also more likely to develop mental and physical health problems in young adulthood, compared to their peers who did not use the drug during adolescence.
These are the conclusions of a new study published in JAMA Network Open.
“This further reinforces the idea that cannabis use in adolescence negatively affects the health trajectory of those who use it,” says psychiatrist Dr. Ryan Sultan from Columbia University, who did not participate in the new research.
The new study used data from the Quebec Longitudinal Study of Child Development. Researchers in Montreal, Canada, have been following more than 1,500 children from birth to young adulthood to understand the factors that influence their development and health. Among the various aspects of the youths’ lives and habits that the scientists recorded is cannabis use between ages 12 and 17.
The researchers found that the majority of teens—60%—did not use cannabis during adolescence. Of the remaining 40%, half started using cannabis in late adolescence and, at age 17, used the drug infrequently—less than once a month. The remaining 20% started using marijuana before age 15 and, at 17, used it at least once a month.
This last group was more likely to seek medical care in young adulthood for mental and physical health problems, compared to those who did not use the drug during adolescence.
“The risk is concentrated among those who start early and use frequently,” says psychologist and lead study author Massimiliano Orri from McGill University.
Early and frequent cannabis users had 51% higher odds of seeking care for mental health problems in young adulthood, compared to those who did not use the drug. And this risk was calculated after controlling for a range of known confounding factors that influence health, such as bullying or lack of parental involvement.
Similarly, early and frequent cannabis users had an 86% higher likelihood of needing physical health care.
“We have indications that respiratory problems were the most frequently reported, as well as accidents and unintentional injuries,” says Orri.
These physical health problems may be related to cannabis intoxication but could also stem from withdrawal symptoms, Orri and his colleagues write in the paper.
“This certainly makes sense,” says psychologist Krista Lisdahl from the University of Wisconsin-Milwaukee, who also studies adolescent brain development and health but did not participate in the new research. “It’s alarming and something we really need to monitor more closely here in the United States as well.”
One of the study’s main strengths is that Orri and his colleagues controlled for many confounding factors, Lisdahl adds.
“There are many factors that are intertwined with both physical and mental health,” says Lisdahl. And the new study controlled for many of them, including “family, parental conflict and parenting style, as well as parental monitoring of teens.” The researchers also analyzed individual-level factors, such as social skills, peer relationships, and whether the youth was a victim of peer bullying.
Previous studies have also found a link between adolescent cannabis use and a higher risk of developing mental health symptoms.
Sultan’s recent research found a two- to fourfold higher likelihood of developing psychiatric disorders in teens who used cannabis recreationally, compared to teens who did not use the drug. Other studies have suggested a link between early cannabis use and psychosis in young people. He and his colleagues have also found a higher risk of other impacts, such as lower grades and absenteeism.
“The adolescent brain continues to develop very dynamically during adolescence and into early adulthood,” says Lisdahl. “Regular use of substances like cannabis during this period can disrupt healthy neural development, especially in brain areas related to executive functions, such as problem-solving, planning, behavior and impulse control, and emotional regulation,” she says.
Consider, for example, a teen prone to anxiety who turns to cannabis to feel less anxious, says Sultan. “If this becomes a regular habit, it becomes the method for dealing with anxiety,” he explains. “It becomes their primary coping strategy, and the person loses the ability to handle anxiety in other ways.”
The same can happen with someone who uses cannabis to manage mood, he adds.
Therefore, for someone already predisposed to certain mental health symptoms, starting cannabis use in adolescence can increase the likelihood that those symptoms worsen over time, evolving into mental disorders.
For all these reasons, Sultan—a child and adolescent psychiatrist—says he often talks with teens and parents about delaying cannabis use until age 25 to minimize the risks of later health and behavioral problems.
Source: npr.org by Rhitu Chatterjee