August 06, 2018
Teenagers who vape or smoke hookah are up to four times more likely to use marijuana two years later, according to a new study conducted by researchers at the University of Pennsylvania and the University of Southern California.
Additionally, the use of e-cigarettes or hookah more than doubles the likelihood that teens will use both tobacco and marijuana by mid-adolescence.
The findings suggest that newer tobacco forms likely increase teenagers' vulnerability to the use of marijuana and the dual use of tobacco and cannabis. Nicotine – a stimulant found in tobacco – "primes the brain's reward system," enhancing the pleasured gained from subsequent drug experiences, according to the researchers.
"We know there's a relationship that exists between conventional cigarette smoking and marijuana use for young people," said Dr. Janet Audrain-McGovern, a psychiatry professor at Penn's Perelman School of Medicine. "Especially for adolescents, combustible smoking has declined over the past decade. But the use of these more novel tobacco products has increased."
The researchers wanted to know whether that same relationship existed with different forms of smoking.
To do so, they surveyed 2,668 freshmen students at 10 public high schools in Los Angeles in 2013, asking whether they had ever used e-cigarettes, traditional or combusitble cigarettes, a hookah water pipe or any form of marijuana.
They then followed up two years later, as the students entered their junior year. This time, the researchers inquired whether the students had ever used combustible, vaped or edible marijuana.
Their findings were published Monday in the medical journal "Pediatrics."
Students who had used hookah as freshman were 3.6 times more likely to have tried marijuana and 4.1 times more likely to have used cannabis within the 30 days prior to the second survey.
Students who had vaped as freshmen were about 3.6 times more likely to have later tried cannabis, or used it within the 30 days prior to the second survey.
"We were not surprised by the findings," Audrain-McGovern said. "The reason why this is concerning is (tobacco) use is much more prevalent now. There's less regulations on the use of the other tobacco products and marijuana use is becoming much more normalized."
More than 11 percent of high school students use e-cigarettes and between 5-to-11 percent smoke hookah, the researchers noted. Also, federal regulations do not restrict youth-targeted advertising or sales of youth-friendly flavors of e-cigarettes and hookah products.
Additional research needs to be conducted to confirm the study's findings, said Audrain-McGovern, who is spearheading a similar cohort in the Philadelphia area.
But based on the findings of the new study, researchers also are intrigued by another questions – why do these associations between tobacco and marijuana use exist?
The researchers found dual use of tobacco and marijuana troubling because it increases the odds of a teenager becoming dependent on both nicotine and cannabis.
"Why is it when a young person uses e-cigarettes or hookah they then go on to use marijuana and then to use both of them?" Audrain-McGovern said. "We can speculate that maybe it's related to this adaptation of the airway. It's easier to inhale subsequent products.
"Is it because you are surrounded by other peers who uses these products? Is it because, somehow, the nicotine has altered your brain, which it does do that. Other drugs you try thereafter, the experience of that is more pleasurable."