A groundbreaking study from McGill University has revealed new insights into how mixing tobacco with cannabis can significantly impact the Cannabis Brain. The research, published in Drug and Alcohol Dependence Reports, offers the first in-vivo evidence that combining the two substances may cause measurable biochemical changes in the Cannabis Brain, potentially explaining why co-users experience worse mental health outcomes.
Tobacco’s Hidden Impact on the Cannabis Brain
According to lead author Rachel Rabin, PhD, the study found that tobacco co-use elevates levels of an enzyme in the Cannabis Brain known as FAAH (fatty acid amide hydrolase). This enzyme regulates endocannabinoids—natural chemicals responsible for mood, motivation, and emotional stability. When FAAH levels rise, these “feel-good” molecules break down more quickly, which may lead to anxiety, depression, or addictive behaviors.
Up to 80% of cannabis users also consume tobacco, often during the same session. While both substances independently affect the endocannabinoid system, this research is the first to examine how their combination uniquely influences the Cannabis Brain.
Measuring Chemical Changes in the Cannabis Brain
The McGill team used advanced positron emission tomography (PET) imaging to observe FAAH activity in several brain regions, including the prefrontal cortex, hippocampus, cerebellum, and striatum. The results showed that participants who used both tobacco and cannabis—called “co-users”—had significantly higher FAAH levels in key areas of the Cannabis Brain than those who used only cannabis.
Interestingly, the study found no link between FAAH activity and the amount of cannabis consumed. Instead, the number of cigarettes smoked per day correlated directly with higher FAAH activity, suggesting that tobacco, not cannabis, is driving this change in the Cannabis Brain.
Implications for the Cannabis Brain and Mental Health
The researchers believe that higher FAAH levels could make the Cannabis Brain more vulnerable to stress, withdrawal symptoms, and emotional instability.
Rabin and her team theorize that tobacco may “sensitize” the endocannabinoid system, forcing the Cannabis Brain to overproduce FAAH as a compensatory mechanism. This biochemical imbalance may increase the risk of addiction and mood disorders over time.
Future Research on the Cannabis Brain
Future studies will explore whether elevated FAAH levels in the Cannabis Brain can predict relapse or long-term mental health issues. As legalization spreads, understanding how substances interact within the Cannabis Brain is essential for promoting safer use and better public health outcomes.
