Marijuana a gateway drug for nicotine?
Usually, smoking cigarettes is seen as a gateway to marijuana use, but new research published in the journal Neuropsychopharmacology found that exposure to marijuana can lead to an addiction to nicotine, at least in mice.
For the study, researchers exposed one group of mice to the chemical tetrahydrocannabinol (THC), which is the active in ingredient in marijuana, and another group of mice to a placebo. Then researchers attempted to teach both groups of mice to self-administer nicotine by giving the mice nicotine whenever they poked their nose through a specific hole in the cage. Not all of the mice successfully learned how to self-administer nicotine, so the ones that did learn the nicotine trigger were presumably more motivated to receive the fix and therefore more addicted to nicotine.
The scientists found that 94 percent of the mice first exposed to THC learned how to self-administer nicotine compared to only 65 percent of the mice that were exposed to the placebo. And, the mice that were first exposed to THC performed on average 17 nose-pokes for a dose of nicotine compared to the placebo mice that performed only 11 nose-pokes.
More research is needed to see if THC has the same effect on humans, but the findings suggest that marijuana exposure can have a lasting impact on the brain that increases a person's risk of becoming addicted to nicotine.