Genetic links between cannabis use and various traits may help guide the creation of prevention and treatment strategies for cannabis use disorders.
Researchers from the University of California, San Diego School of Medicine, working with the genetic testing company 23andMe, have pinpointed specific regions in the human genome linked to cannabis use. Their findings reveal new genetic connections between cannabis use and aspects of mental, cognitive, and physical health. These insights could eventually support the development of improved prevention and treatment strategies for cannabis use disorder. The study was recently published in Molecular Psychiatry.
“Cannabis is widely used, but its long-term effects on health remain poorly characterized,” said Sandra Sanchez-Roige, Ph.D., associate professor of psychiatry at UC San Diego School of Medicine and senior author of the study. The researchers were also interested in the relationship between genetics and traits that contribute to the development of cannabis use disorder, which can interfere with a person’s daily life.
“While most people who try cannabis do not go on to develop cannabis use disorder, some studies estimate that nearly 30% will,” said Sanchez-Roige. “Understanding the genetics of early-stage behaviors may help clarify who is at greater risk, opening the door to prevention and intervention strategies.”
To investigate these links, the researchers conducted a genome-wide association study (GWAS) examining how genetic variation relates to cannabis use. The analysis included data from 131,895 23andMe research participants who provided information on whether they had ever used cannabis. Those who reported prior use also indicated how frequently they consumed it.
“We’ve known for decades that genetic factors influence whether or not people will try drugs, how frequently they use those drugs, and the risk that they will become addicted to them,” said Abraham A. Palmer, Ph.D., professor and vice chair for basic research in the department of psychiatry at UC San Diego School of Medicine and co-author of the study. “Genetic tools like GWAS help us identify the molecular systems that connect cannabis use to brain function and behavior.”
Key Genes Identified
The study found that lifetime cannabis use was associated with two genes. The first was Cell Adhesion Molecule 2 (CADM2), a gene involved in cell assembly and in signaling between nerve cells, particularly in the brain. Previous studies have linked CADM2 to various traits and conditions, including impulsive personality, obesity, and cancer metastasis. Frequency of cannabis use was also found to be associated with the CADM2 gene.
The second gene was Metabotropic Glutamate Receptor 3 (GRM3), which is involved in communication between neurons and long-term brain plasticity. GRM3 has already been linked to psychiatric disorders, including schizophrenia and bipolar disorder.
“We showed that the genetics of cannabis use — both trying it and using it more often — are tied to the genetics of other psychiatric traits, cognitive measures, and even physical health problems,” said Sanchez-Roige.
A secondary analysis revealed an additional 40 genes associated with lifetime cannabis use and four genes associated with frequency of cannabis use. Twenty-nine of these genes had not previously been associated with cannabis-related traits.
The researchers then analyzed which health conditions were correlated with a genetic predisposition for cannabis use. They analyzed thousands of traits in two large independent datasets from the National Institutes of Health’s (NIH) All of Us Research Program and Vanderbilt University Medical Center’s biobank.
Across the genome, lifetime cannabis use and frequency of cannabis use were genetically correlated with more than 100 different traits including psychiatric conditions (e.g., schizophrenia, ADHD, anxiety, and depression), cognitive traits (e.g., executive function and risk-taking,) and physical health (e.g., diabetes, chronic pain, and coronary artery disease). They were also associated with an increased risk for tobacco use, infectious diseases including HIV and viral hepatitis, and autoimmune diseases.
Mapping Genetic Risk Before Disorder Development
The study is one of the first genome-wide association studies to examine behaviors that precede cannabis use disorder.
“Cannabis use exists on a continuum,” said first author Hayley Thorpe, Ph.D., a visiting scholar in Sanchez-Roige’s lab and postdoctoral researcher at Western University. “By studying these intermediate traits, we can begin to map how genetic risk unfolds before cannabis use disorder develops.”
There are currently no FDA-approved drug therapies to treat cannabis use disorder. The authors hope that the biological discoveries generated by GWAS will support future efforts to identify therapeutic targets and preventative interventions against the disorder.
Reference: “Integrating biological and environmental data to solve key scientific and societal challenges” by David M Kunkel, Brooke L Long-Fox, Cameron Pittman, Julia Portmann, Matthew Sheik, John M Bates, Andrew Bentley, Dori L Contreras, Elizabeth R Ellwood, Michael W Lomas, Anna K Monfils, William E Moser, Gil Nelson, Sinlan Poo, Barbara Thiers, Gregory J Watkins-Colwell, Michael S Webster, Breda M Zimkus and Jyotsna L Pandey, 15 October 2025, BioScience.
DOI: 10.1093/biosci/biaf150
The study was funded, in part, by the National Institutes of Institute on Drug Abuse (grants R01 DA050721, P50DA037844 and P30DA060810) at the NIH, and the Tobacco-Related Disease Research Program (grant T32IR5226).
The 23andMe Research participants provided informed consent and volunteered to participate in the research online, under a protocol approved by the Association for Accreditation of Human Research Protection Programs, Inc. (AAHRPP)-accredited Salus IRB.
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7 Comments
Study reported on and cited s.b. https://www.nature.com/articles/s41380-025-03219-2 .
And also in the availability of the stuff.
I know long-term users and they display psychotic, chaotic behavior. A health epidemic.
Smoking for 55 years now more than ever.
Functioned at a very high level in my careers.
Have several of the conditions listed.
My uncle smoked from 15 to 80, when he quit, 5 years before passing.
I don’t touch the stuff, but I’ve observed that in others who use it frequently and long term, their emotions are out of control and way overblown so that they completely overreact to everything. Their lives were basically destroyed by pot. Also, that middle-aged pot users seem to have some dementia or senility like that of an 80 year old.
This belief that pot is safe is completely wrong and it’s destroying people’s lives. Plus, inhaling smoke of any kind on a regular basis is one of the worst things you can do to your lungs.
I wish people could just learn to accept that life is suffering and the world basically sucks. Embrace the suck and you won’t need drugs. “Life is pain, highness. Anyone who tells you otherwise is selling something.” — from The Princess Bride
“I wish people could just learn to accept that life is suffering and the world basically sucks.” Sounds like you need to chill and smoke some weed.
Anothee poorly done study. Correlation is NOT causation. I’ll bet all the study subjects were male or female, so lifetime x and y chromosomes are even more correlated. The fear mongering about the “evils of Marijuana” will never end… and 30% will developed cannabis misuse syndrome.. where did that come from.