Cannabis and Tobacco Co-Use: What a Small FAAH Brain Study Found

A small brain-imaging study raises questions about how tobacco co-use relates to the endocannabinoid system in people who use cannabis. Its findings are preliminary: an imaging difference is not a direct measurement of happiness, anandamide concentration, or a person’s likelihood of relapse.

What Researchers Measured

The 2025 study in Drug and Alcohol Dependence Reports compared five cannabis users who smoked tobacco daily with eight cannabis users without current tobacco use. Researchers used PET imaging with the tracer [11C]CURB to assess FAAH, accounting for sex and FAAH genotype.

FAAH breaks down anandamide, an endocannabinoid sometimes nicknamed the “bliss molecule.” The study assessed FAAH-related imaging signals, not anandamide concentrations directly.

What the Findings Support

Co-users had higher FAAH measures in the substantia nigra and cerebellum after correction for multiple comparisons. A sensorimotor-striatum result was a statistical trend, not a significant finding at the conventional threshold.

This was an analysis of previously collected data, without a tobacco-only comparison group. It cannot establish that nicotine alone caused the difference, that combining the substances lowered anandamide, or that the imaging finding caused depression, anxiety, or relapse. The small sample also limits generalization.

Why the Anandamide Hypothesis Matters

McGill’s research announcement describes FAAH as a possible target for future medication development. The proposed connection between FAAH, endocannabinoid signaling, and clinical outcomes is a research direction rather than an established treatment pathway.

The “bliss molecule” nickname can obscure that distinction. A biological marker does not give a complete account of mood, dependence, or recovery. Establishing clinical usefulness would require evidence that a treatment improves outcomes people care about, not merely that it changes a laboratory or imaging measure.

Treatment Research Is Different From Available Care

There are currently no FDA-approved medications for cannabis use disorder. NIH continues to support development of medications and other interventions. The PET study should not be read as a recommendation to take an FAAH inhibitor or a supplement marketed as increasing anandamide.

NIDA describes behavioral approaches such as cognitive behavioral therapy, motivational enhancement, and contingency management for cannabis use disorder. Care can address both substance use and associated mental health concerns.

Support for People Who Use Both Substances

Tell a healthcare professional about both cannabis and tobacco, including frequency, products, previous quit attempts, and symptoms when cutting down. A treatment discussion does not require a brain scan or an explanation based on a single molecule.

For cigarette smoking, CDC recommends support that can include counseling and cessation medicines. Options include nicotine replacement and prescription medicines selected with a clinician. In the United States, 1-800-QUIT-NOW provides free quitline support. These established options should be distinguished from experimental approaches suggested by early neuroscience findings.