A recent study has uncovered two genes that may influence an individual’s interest and habits regarding cannabis use. Researchers from Western University in Canada, the University of California, San Diego (UC San Diego), and the personal genomics company 23andMe analyzed the genomes of 131,895 individuals along with their self-reported cannabis usage frequency. This groundbreaking research not only identified genetic variations linked to cannabis use but also connected these patterns to over a hundred other physical and mental health traits.
The study emphasizes the complexity of factors influencing drug use. While environmental factors, such as socioeconomic status and geographic location, play significant roles, genetic predispositions can subtly affect an individual’s likelihood of experimenting with drugs. As Sandra Sanchez-Roige, a professor of psychiatry at UC San Diego, explains, “While most people who try cannabis do not go on to develop cannabis use disorder, some studies estimate that nearly 30 percent will.” Understanding the genetic factors associated with early cannabis use could aid in developing prevention and intervention strategies.
Key Genetic Findings
The research highlighted two specific genes: Cell Adhesion Molecule 2 (CADM2) and Metabotropic Glutamate Receptor 3 (GRM3). The CADM2 gene, previously linked to cannabis use, plays a crucial role in cell assembly and communication between nerve cells. The study found that variations in CADM2 correlate with both lifetime cannabis use and frequency of use. In contrast, GRM3, which contributes to neuronal signaling and brain plasticity and has been associated with various psychiatric disorders, had not been previously linked to cannabis consumption.
The researchers also explored how these new genetic variations might affect the expression and function of these genes. Their findings revealed overlaps with conditions such as anxiety, depression, cognitive function, and diabetes, indicating a complex interplay between cannabis use and broader health issues. As Sanchez-Roige noted, “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.”
Modest Genetic Influence
Despite the significance of these findings, the genetic influence on cannabis use remains modest. The study suggests that genetics account for just under 13 percent of the variation in whether individuals have tried cannabis at some point in their lives, and only 6 percent of the variation in the frequency of use. This indicates that while genetics play a role, other factors are likely more impactful in determining cannabis habits.
According to Hayley Thorpe, a neuroscientist at Western University, “Cannabis use exists on a continuum. By studying these intermediate traits, we can begin to map how genetic risk unfolds before cannabis use disorder develops.”
The implications of this research are far-reaching, potentially paving the way for enhanced understanding of cannabis use and its relationships with a range of health issues. The findings have been published in the journal Molecular Psychiatry, further contributing to the growing body of knowledge surrounding the genetic factors influencing substance use.
