Jan. 24 (UPI) -- Teens who smoke cannabis with joints or bongs, or who use some pot concentrates, are six times more likely to continue using the drug than those who consume it via other methods, a new analysis suggests.
In results published Friday by JAMA Network Open, researchers found in a survey of nearly 3,000 teens, the highest percentage -- approximately 6 percent -- reported prior use of "combustible cannabis," while less than 1 percent said they had "vaped" the substance.
Teens who said they smoked marijuana in a joint or bong were found to be at higher risk for still smoking six and 12-months later, the authors found.
Researchers write in the study that, for cannabis control and efforts to keep it out of the hands of teens, officials should consider targeting pot products that teens are more likely to use -- and that are more likely to attract them to keep doing so.
"We report that the type of cannabis product matters," study co-author Jessica Barrington-Trimis, director of the USC Epidemiology of Substance Use, told UPI. "These findings extend beyond an investigation simply of experimentation to an investigation of continued use."
In recent years, the legalization and commercialization of cannabis has increased the variety of products available that contain THC, the psychoactive chemical in pot that gets people high. While smoking joints or bongs remains popular, there are also "edible" products -- or food items containing cannabis -- as well as "cannabis concentrates," highly concentrated products that include "wax," "shatter," "budder" and butane hash oil.
Although less than 1 percent of the teens surveyed in Barrington-Trimis' study reported use of cannabis concentrates, those users were also nearly six times more likely to have continued and increased their consumption of the drug over a 12-month period.
Barrington-Trimis noted that research from the University of Michigan's Monitoring the Future project has found that in 2018 more than 40 percent of high school seniors reported using cannabis, with more than 20 percent indicating at least semi-regular use.
To learn what specific cannabis products are particularly appealing to teens, Barrington-Trimis and her colleagues -- who have focused earlier work on teen vaping -- surveyed 3,065 students at 10 high schools in southern California in the spring of 2016. In all, 2,685 were included in the final analysis, and they were interviewed three times -- at the beginning, and then six and 12 months later.
Among those surveyed, 158, or 5.9 percent, reported using combustible cannabis on one to two of the previous 30 days, while 90, or 3.4 percent, indicated they had smoked blunts. In addition, 78, or 2.9 percent, reported edible cannabis use, while 17 and 15, or 0.6 percent each, indicated that they vaped cannabis or used a concentrate.
Although all of these percentages are relatively low, the authors noted that many respondents reported using multiple cannabis-based products.
Additionally, teens who said they used a cannabis concentrate on one to two of the prior 30 days during the initial interview said they consumed the products a mean of 9.42 more days in a month during the six- and 12-month follow-up interviews.
"In other words, the risk of persistent cannabis use and progression to more frequent cannabis use was greatest for those experimenting with concentrate cannabis use," Barrington-Trimis said. "There are a number of mechanisms that we propose in the discussion section of the paper, which outline some reasons which may explain these findings."