Mixing Popular Drugs, Marijuana And Tobacco, May Increase Risk Of Psychological Dependence

An added dose of marijuana to your typical tobacco puff may make it harder for you to quit either drug, but especially the latter, a new study published Tuesday in Frontiers in Psychiatry indicates.

The researchers took a look at selected responses from over 30,000 participants enrolled in the 2014 Global Drug Survey, purportedly the largest online survey of current drug users to date. All had taken cannabis at least once in the past 12 months, and the researchers sought to figure out whether concurrent tobacco use was a possible risk factor for drug dependence. The participants were asked which methods they most commonly used to take cannabis, whether they regularly combined tobacco with it, and whether they wanted to cut back or quit either drug in the near future.

Globally, the patterns of drug use varied significantly. While American citizens and their neighbors rarely used routes of administration that combined both drugs, such as smoking a joint, blunt, or pipe filled with tobacco, the opposite was true of people living in Europe and Australia. In total, two-thirds of everyone polled had regularly imbibed both at once, nearly always through a joint, and only 16 percent had never tried smoking tobacco. Sixty-two percent voiced a desire to cut back on tobacco in the next year, but the odds of saying so were 10 percent higher in those who didn’t routinely use tobacco and cannabis together. Similarly, these more exclusive users were 80 percent more likely to want help quitting tobacco, and over twice as likely to plan seeking that help.

Smoking Frank Peters rolls a marijuana cigarette during a demonstration in front of the San Francisco Hall of Justice July 12, 2005 in San Francisco, California. Justin Sullivan/Getty Images

"Cannabis dependence and tobacco dependence manifest in similar ways, so it is often difficult to separate these out in people who use both drugs," said lead author Chandni Hindocha, a doctoral student at the Clinical Psychopharmacology Unit of University College London, in a statement. "Cannabis is less addictive than tobacco, but we show here that mixing tobacco with cannabis lowers the motivation to quit using these drugs."

Tobacco’s influence on cannabis dependence was more muddled, though. People who used both were less likely to want help slowing their pot habit down, but they were actually more likely to express a desire to do so in the first place, and there was no clear relationship between the type of drug use and a willingness to proactively plan to seek help for quitting marijuana. Those who regularly used methods without tobacco reported using cannabis more often as well as better rated their enjoyment of the method than those who didn’t. In total, only 27 percent wished to cut back on marijuana within the next year.

Because tobacco is certainly more dangerous than marijuana and may increase the potency and health hazards of marijuana when taken together, the researchers believe their results highlight the need to focus more narrowly on discouraging methods of marijuana use that incorporate tobacco rather than marijuana use itself; for example, by promoting the vaporizers that have increasingly become popular in the United States and Canada (11 percent and 13 percent reported regular use of these products in the current sample). Vaporizers may even cause less harm to the respiratory system than other routes of use.

“Given a changing legislative environment surrounding access to cannabis in many jurisdictions, increased research focus should be given to reducing the use of routes of administration that involve the co-administration of tobacco," said co-author Dr. Michael T. Lynskey, a researcher at the National Addictions Center of the Institute of Psychiatry, Psychology & Neuroscience located within King's College London.

Source: Hindocha C, Freeman T, Ferris J, et al. No Smoke without Tobacco: A Global Overview of Cannabis and Tobacco Routes of Administration and Their Association with Intention to Quit. Frontiers in Psychiatry. 2016

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