Marijuana, also known as cannabis, has become much more common in recent years as more places have legalized its medical or recreational use.
In the United States, the Centers for Disease Control and Prevention estimates that about 48.2 million people, or around 18% of the population, used marijuana in 2019. As its popularity continues to grow, scientists are working to better understand how regular cannabis use affects the human body over the long term.
While some studies have suggested possible medical benefits for certain conditions, many important questions remain unanswered. A new study from Northwestern Medicine has found evidence that marijuana use may be linked to changes in the way our DNA works. The findings were published in the journal Molecular Psychiatry.
Marijuana comes from the Cannabis sativa plant. People use it in many different ways. Some smoke it in hand-rolled cigarettes called joints or in water pipes known as bongs. Others consume it in foods, drinks, oils, or other products.
The main mind-altering ingredient is tetrahydrocannabinol, or THC, although the plant also contains many other natural compounds, including cannabidiol, or CBD.
DNA carries the instructions that tell our cells how to grow, repair themselves, and perform their daily functions. Although the DNA sequence usually stays the same throughout life, chemical changes can affect how genes are turned on or off. One of these changes is called DNA methylation.
During this process, tiny chemical groups attach to DNA and influence whether certain genes become more or less active. Scientists believe DNA methylation plays an important role in normal development, aging, and many diseases.
To investigate whether marijuana use might affect DNA methylation, researchers led by Dr. Lifang Hou studied blood samples collected from more than 900 adults. The samples came from participants in a long-running heart health study who had provided blood samples about five years apart.
The researchers also collected information about each person’s marijuana use, including whether they had used it recently and how much they had used during their lifetime.
After analyzing the DNA, the researchers found a clear association between marijuana use and changes in DNA methylation. Depending on how marijuana use was measured, they identified between 16 and 132 genetic markers that appeared to be linked with cannabis exposure.
Many of these DNA changes were located in areas involved in important biological functions such as cell growth, hormone regulation, and the immune system. Some of the affected genes had also been linked in previous research to mental health conditions including schizophrenia, bipolar disorder, and substance use disorders.
The researchers emphasize that these findings do not prove marijuana directly causes these DNA changes or that the changes themselves lead to disease.
The study only shows an association between marijuana use and differences in DNA methylation. Other factors, including lifestyle, environment, genetics, or overall health, could also play a role. More research will be needed before scientists can fully understand the relationship.
Even so, the findings are important because they suggest marijuana may influence the body’s biology in ways that extend beyond its immediate effects on the brain.
Understanding these changes could help researchers investigate whether long-term cannabis use affects the risk of heart disease, cancer, mental illness, immune disorders, or other health conditions.
The researchers also hope future studies will examine whether these DNA changes are temporary or long-lasting, whether they differ between occasional and heavy users, and whether age, genetics, or other personal factors influence the results.
As marijuana becomes more widely available, answering these questions will become increasingly important for both doctors and the public.
Although cannabis may offer medical benefits for some patients under professional supervision, this study reminds us that no widely used substance is completely understood. Decisions about marijuana use should consider both its possible benefits and its potential risks.
The Northwestern Medicine research represents another step toward understanding how marijuana affects the body at the molecular level.
As more high-quality studies become available, scientists hope to build a clearer picture of how cannabis influences human health over a lifetime and provide better information for patients, healthcare providers, and policymakers.
If you care about cannabis, please read studies that what you need to know about cannabis and heart attack, and CBD from cannabis may help inhibit COVID-19 infection.
For more information about cannabis, please see recent studies that medical cannabis could help reduce depression, and results showing this stuff in cannabis may protect aging brain, treat Alzheimer’s.
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