Cannabis and Your DNA: What Science Says About Epigenetic Changes

As cannabis becomes more widely accepted and legal across the globe, researchers are uncovering fascinating insights about its impact on the human body. Beyond the immediate effects on mood or pain, cannabis use may have deeper, long-term influences at the molecular level. A recent study involving over 1,000 adults found evidence suggesting that cannabis use could cause changes to the epigenome—the biological system that controls how our genes are expressed.

This emerging research raises questions about the potential health implications of cannabis use and its role in shaping gene activity over time.

Think of the epigenome as a set of switches for our DNA. While our genetic code remains constant, the epigenome determines how, when, and where specific genes are turned on or off. These changes can influence how our bodies function, affecting everything from hormone levels to immune responses.

One of the most studied forms of epigenetic modification is DNA methylation—the addition or removal of methyl groups to the DNA strand. These molecular changes can make it harder for the cellular machinery to read genetic instructions, effectively altering gene activity without changing the underlying DNA sequence.

Environmental and lifestyle factors, like diet, stress, and substance use, can influence DNA methylation, leaving a biological fingerprint that reflects our life experiences. In some cases, these changes can even be passed on to future generations.

In a groundbreaking study led by researchers at Northwestern University, scientists analyzed blood samples from participants in a long-term research project spanning two decades. These individuals, aged 18 to 30 at the start of the study, reported their cannabis use over the years and provided blood samples at the 15- and 20-year marks.

Using these samples, the researchers examined patterns of DNA methylation and found numerous markers associated with cannabis use:

At the 15-year mark: 22 DNA methylation markers were linked to recent cannabis use, while 31 were associated with cumulative use over time.

At the 20-year mark: 132 markers were tied to recent use, and 16 to cumulative use.

Interestingly, one marker associated with cannabis use had also been previously linked to tobacco use, suggesting a potential overlap in how these substances affect the epigenome.

While the study doesn’t establish a direct cause-and-effect relationship between cannabis use and health problems, it does provide intriguing clues. Many of the identified epigenetic changes have been associated with:

Neurological disorders: Conditions like schizophrenia and bipolar disorder.

Cellular processes: Changes in cellular proliferation and hormone signaling.

Substance use disorders: Links to addiction-related pathways.

Immune system responses: Modifications that could influence how the body handles infections or inflammation.

These findings hint at cannabis's potential to influence various biological systems, though much remains to be understood.

With nearly half of U.S. adults reporting they’ve used cannabis at least once, understanding its long-term health effects is more critical than ever. As epidemiologist Lifang Hou, the study’s lead author, explains, “This research has provided novel insights into the association between marijuana use and epigenetic factors.”

The study also highlights the need for further research, particularly in diverse populations, to confirm these findings and explore their implications. 1“Studies examining the effect of marijuana on age-related health outcomes may provide further insight into the long-term effects of marijuana on health,” added researcher Drew Nannini.

As cannabis legalization continues to expand, understanding its full range of effects is vital for informed public health policies. While cannabis has shown promise for managing conditions like chronic pain, anxiety, and PTSD, the possibility of long-term epigenetic changes adds a layer of complexity to its risk-benefit analysis.

For now, this research serves as a reminder that substances we consume can leave lasting marks—not just on us, but potentially on future generations.

Should More Research Be Done on Cannabis’s Long-Term Genetic Effects?