A sweeping genetic study involving more than 130,000 participants has uncovered striking connections between the genes that influence cannabis use and a wide range of psychiatric, cognitive, and physical health traits — including schizophrenia, impulsivity, diabetes, and chronic pain.
Researchers from the University of California San Diego School of Medicine, in collaboration with 23andMe, identified specific regions of the human genome that appear to shape a person’s likelihood of trying cannabis and how often they use it. The findings, published on October 13, 2025, in Molecular Psychiatry, could pave the way for more targeted prevention and treatment strategies for cannabis use disorder (CUD) — a condition that can significantly disrupt daily life.
“Cannabis is widely used, but its long-term effects on health remain poorly understood,” said Dr. Sandra Sanchez-Roige, senior author of the study. “By uncovering the genetics behind early use behaviors, we can begin to identify who may be more vulnerable to developing cannabis use disorder.”
Genetic Clues to Cannabis Behavior
While most people who experiment with cannabis do not become dependent, studies suggest that nearly one in three may develop problematic use patterns over time.
To understand why, the team conducted a genome-wide association study (GWAS) using genetic and survey data from 131,895 participants who consented to 23andMe’s research program. Respondents reported whether they had ever used cannabis and how frequently they consumed it.
“We’ve long known that genes play a role in drug experimentation, frequency, and addiction risk,” said Dr. Abraham Palmer, co-author and vice chair for basic research in psychiatry at UC San Diego. “Now, GWAS allows us to pinpoint the molecular systems that link cannabis use with brain function and behavior.”
Among the discoveries were two key genes:
- CADM2 (Cell Adhesion Molecule 2) — a gene involved in how brain cells connect and communicate, previously tied to impulsivity, obesity, and even cancer metastasis. It was linked to both lifetime cannabis use and usage frequency.
- GRM3 (Metabotropic Glutamate Receptor 3) — a gene influencing how neurons communicate and adapt, previously associated with schizophrenia and bipolar disorder.
From Genes to Health Risks
The researchers also identified 40 additional genes associated with cannabis use, 29 of which had never before been linked to cannabis-related behaviors.
When they compared genetic data with large public health databases — including the NIH All of Us Research Programand Vanderbilt University’s biobank — the team found that the same genetic patterns connected cannabis use to over 100 traits, such as:
- Mental health conditions — schizophrenia, ADHD, anxiety, depression
- Cognitive traits — risk-taking, executive function
- Physical conditions — diabetes, chronic pain, coronary artery disease
- Behavioral and infectious risks — tobacco use, HIV, hepatitis, autoimmune disorders
“By studying intermediate traits — the behaviors and predispositions that come before a disorder develops — we can map how genetic risk unfolds,” said Dr. Hayley Thorpe, the study’s first author.
Currently, there are no FDA-approved medications for cannabis use disorder. Researchers hope these findings will lead to new therapeutic targets and personalized prevention strategies — a crucial step as cannabis becomes increasingly normalized and accessible worldwide.
Further Reading on Cannabis and Health
For more insights into cannabis science and health trends, explore our related articles on how dispensaries may influence alcohol use in Oregon, the truth behind cannabis aroma and terpenes, and why THC beverages are becoming the next big alcohol alternative in 2025.
FAQ: Understanding Key Terms
1. What is a Genome-Wide Association Study (GWAS)?
A GWAS is a research method that scans the entire genome of many individuals to find genetic variations linked to a specific trait, such as cannabis use or disease susceptibility.
2. What does the gene CADM2 do?
CADM2 helps nerve cells form connections in the brain. It has been linked to impulsivity, obesity, and now, how often people use cannabis.
3. What is Cannabis Use Disorder (CUD)?
CUD is a medical condition where a person’s cannabis consumption causes significant impairment or distress, often affecting relationships, work, or health.
4. What are Metabotropic Glutamate Receptors (like GRM3)?
These are proteins in the brain that help regulate how neurons communicate. Changes in GRM3 activity have been connected to psychiatric conditions such as schizophrenia.
