The use of cannabis and tobacco often reduce the neuro-connectivity in the brains of people who consume one or the other separately. However, this is not the case with people who consume both.
Both cannabis and tobacco affect the brain in different ways. And while there is an established body of research evaluating exactly what these effects are, very few studies have looked at what happens in the brain form people who smoke both substances. And that has created a big gap in our understanding of these substances, according to Dr. Francesca M. Filbey, who hopes to fill that gap with her recent research.
"Most of the literature to date has focused on associations of isolated cannabis and nicotine use, even though concurrent cannabis and nicotine use is more prevalent in society than cannabis use alone," Filbey - the Bert Moore Chair in BrainHealth at UT Dallas - said in a statement. "Our findings confirm the limitations of existing research."
Using MRI scans Filbey examined the neuro-activity of people in four groups. The first was comprised of tobacco consumers, the second of marijuana consumers, the third of people who use both substances and a control group that did not consume either. The scans showed that the control group had the greatest connectivity in most scenarios, while the only-cannabis and only-tobacco groups showed less (though to varying degrees). The group of people who consumed both cannabis and tobacco had results that were most similar to the control group with higher neuro-connectivity than either of the one substances groups.
These findings seem to suggests that tobacco and cannabis may counteract some of the effects of each other in the brain, though more research is needed to solidify that conclusion. Nevertheless, Fibley hypothesizes that developing a greater understanding of the interactions between these two substances will be useful in developing programs for people who are looking to quit.