Khaberni - A preliminary study found that people who use cannabis and tobacco together suffer from brain changes that may increase the risk of addiction and exacerbate mental health issues, compared to those who use just one.
Researchers conducted brain scans on eight participants who used cannabis only, and five participants who used both tobacco and cannabis. They found that the latter group had higher levels of a principal enzyme in various brain areas, called "fatty acid amide hydrolase" (FAAH), an enzyme that interacts with the "endocannabinoid" system, which controls levels of a neurotransmitter associated with feelings of joy.
Recent studies on animals suggest that FAAH could affect nicotine reward systems, but it is still unclear whether this occurs in humans. Furthermore, some genetic variations in FAAH are associated with an increased risk of addiction and higher anxiety levels.
The principal researcher, Rachel Rabin, a professor of psychology at McGill University in Canada, said: "This is the first evidence in humans of a molecular mechanism that could be behind worse outcomes for users of cannabis and tobacco."
The study did not include individuals who only smoked tobacco, which means the effect of tobacco alone on the brain has yet to be analyzed. Researchers hope to conduct more studies to understand whether cannabis increases these changes or poses a greater risk to mental health when combined with tobacco.
On her part, Romina Mizrahi, the co-author and psychiatrist, said: "We were amazed by the strength of the impact and the clarity of the difference between those who used only cannabis and those who combined it with tobacco."
The researchers explained that most current studies are observational, preventing proof of causality, and often do not consider the amount of tobacco or cannabis used, which could affect the results. However, it seems reasonable to assume that the combination of tobacco and cannabis has different effects than cannabis alone, and future studies will reveal more about these effects.
The study was published in the Journal of Drug and Alcohol Addiction Reports.
