A Comprehensive Genetic Study Links Cannabis Use to Mental, Cognitive, and Physical Health
A comprehensive genetic study has established a link between cannabis use and mental, cognitive, and physical health. Researchers from the University of California San Diego School of Medicine, in collaboration with the genetic testing company 23andMe, have identified several regions of the human genome associated with cannabis consumption. Their findings, published on Monday, October 13, 2025, in the journal Molecular Psychiatry and reported by UC San Diego Today, reveal new connections between cannabis use and various aspects of psychiatric, cognitive, and physical health. These discoveries could inform future prevention and treatment strategies for cannabis use disorders.
"Cannabis is widely consumed, yet its long-term effects on health remain poorly understood," says Sandra Sanchez-Roige, an associate professor of psychiatry at UC San Diego and the lead author of the study. The team focused on genetic factors that may increase the likelihood of developing cannabis use disorder, a condition that can disrupt the daily lives of affected individuals.
According to Sanchez-Roige, "Although most consumers do not develop dependence, nearly 30% may be affected. Understanding the genetic basis of early consumption behaviors could help identify at-risk individuals and develop targeted prevention strategies."
The researchers conducted a genome-wide association study (GWAS) involving 131,895 participants from 23andMe, who answered questions regarding their cannabis use and frequency.
"It has long been known that genetic factors influence the likelihood of trying a drug, frequency of use, and risk of dependence," notes Abraham A. Palmer, a professor and vice president of basic research at UC San Diego. "Genetic tools like GWAS help us identify the molecular systems linking cannabis use to brain function and behavior."
The study highlighted two main genes associated with lifetime cannabis use: CADM2 and GRM3. CADM2 plays a role in communication between nerve cells and has previously been linked to impulsivity, obesity, and certain cancers. GRM3, involved in long-term brain plasticity, is associated with psychiatric disorders such as schizophrenia and bipolar disorder.
A supplementary analysis identified 40 other genes associated with lifetime cannabis use and 4 linked to frequency of use, of which 29 had never been related to cannabis-associated traits before.
The researchers then examined correlations between genetic predisposition to cannabis use and various pathologies using two large American databases: the NIH's All of Us program and the Vanderbilt University Medical Center biobank. They observed genetic links with over 100 different traits, including:
- Psychiatric disorders (schizophrenia, ADHD, anxiety, depression),
- Cognitive characteristics (executive function, risk-taking),
- Physical health issues (diabetes, chronic pain, coronary artery disease).
Correlations were also noted with an increased predisposition to tobacco use, certain infectious diseases (such as HIV or viral hepatitis), and autoimmune diseases.
For Hayley Thorpe, the study's first author and a visiting researcher at UC San Diego, "cannabis use exists on a continuum. By studying intermediate behaviors, we can better understand how genetic risk manifests before a disorder develops."
To date, there are no FDA-approved medications for cannabis-related disorders. The researchers hope these genetic discoveries will help identify new therapeutic targets and develop more effective preventive interventions.
The study was partly funded by the National Institute on Drug Abuse (NIH) and the Tobacco-Related Disease Research Program. Participants from 23andMe provided informed consent to participate in the research, in accordance with ethical protocols approved by the Salus IRB.
Source: UC San Diego Today