Researchers from UC San Diego and 23andMe have discovered genetic links to cannabis use behaviors, connecting them to over 100 health traits. The study, published on October 13, 2025, in Molecular Psychiatry, highlights two key genes and could inform prevention of cannabis use disorder. It analyzed data from nearly 132,000 participants to explore early-stage risks.
A collaborative study between the University of California San Diego School of Medicine and the genetic testing company 23andMe has identified regions of the human genome associated with cannabis use. Published on October 13, 2025, in Molecular Psychiatry, the research used a genome-wide association study (GWAS) on genetic data from 131,895 23andMe participants who reported on their cannabis use via surveys.
"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 and senior author. The team focused on behaviors preceding cannabis use disorder, noting that while most users do not develop the condition, nearly 30% may do so.
Two genes emerged as significantly linked to lifetime cannabis use: Cell Adhesion Molecule 2 (CADM2), which aids nerve cell connections and has prior ties to impulsivity, obesity, and cancer metastasis; and Metabotropic Glutamate Receptor 3 (GRM3), involved in neuron communication and previously connected to schizophrenia and bipolar disorder. CADM2 was also associated with frequency of use.
A secondary analysis found 40 additional genes for lifetime use and four for frequency, with 29 previously unlinked to cannabis traits. Genome-wide, cannabis use correlated genetically with over 100 traits, including psychiatric conditions like schizophrenia, ADHD, anxiety, and depression; cognitive measures such as executive function and risk-taking; and physical issues including diabetes, chronic pain, coronary artery disease, tobacco use, HIV, viral hepatitis, and autoimmune diseases. These correlations were confirmed using datasets from the NIH's All of Us Research Program and Vanderbilt University Medical Center's biobank.
"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 co-author Abraham A. Palmer, Ph.D. The findings, one of the first GWAS on pre-disorder behaviors, aim to support future therapies, as no FDA-approved treatments exist for cannabis use disorder.
"Cannabis use exists on a continuum," added first author Hayley Thorpe, Ph.D. "By studying these intermediate traits, we can begin to map how genetic risk unfolds before cannabis use disorder develops."