Cannabis Use Disorder Was Linked to Lower Oral Microbiome Diversity | Research

The takeaway

Young adults with cannabis use disorder had significantly lower oral bacterial diversity and distinct microbial profiles compared to those with other substance use disorders, with heavier use associated with more anaerobic bacteria.

Oral health researchers, addiction researchers, microbiome scientists

Cannabis use disorder was linked to lower oral bacterial diversity and increased anaerobic bacteria

What the researchers found

Compared to a non-CUD substance use disorder control group, the CUD group exhibited significantly lower alpha diversity (fewer types of bacteria), distinct beta diversity (different bacterial community composition), and differences in specific bacterial taxa. Among CUD participants, more frequent cannabis use was linked to lower diversity, and both frequency and amount were associated with higher abundances of strict anaerobes.

Why it matters

The oral microbiome affects whole-body health, from cardiovascular disease to mental health. Finding that cannabis use disorder specifically alters oral bacterial communities could reveal biological pathways linking heavy cannabis use to broader health outcomes.

The numbers in context

192 participants; 129 with CUD, 63 with non-CUD SUD; CUD had lower alpha diversity; distinct beta diversity between groups; greater cannabis frequency linked to lower diversity; frequency and amount linked to higher strict anaerobe abundance; controlled for sequencing batch, age, sex, race, BMI, alcohol

How the study worked

192 young adults (ages 18-25) with CUD (n=129) or non-CUD substance use disorder (n=63) provided saliva samples for 16S rRNA gene sequencing. The non-CUD SUD control group helped isolate cannabis-specific effects in a population that commonly uses multiple substances. Analyses controlled for batch, age, sex, race, BMI, and alcohol use.

What this study cannot tell us

Cross-sectional design cannot determine if cannabis caused the microbiome changes, all participants had substance use disorders limiting generalizability, self-reported cannabis use, saliva sampling captures only part of the oral microbiome, no longitudinal follow-up

How to read the evidence

Well-controlled comparison against other SUD patients with molecular methods; moderate sample size but cross-sectional design

When this study was published

Published 2025

The bigger picture

The shift toward anaerobic bacteria in heavy cannabis users mirrors patterns seen in periodontal disease and some systemic conditions. This suggests that cannabis use may create an oral environment that promotes harmful bacteria, with potential downstream health effects beyond the mouth.

Questions still open

Does the altered oral microbiome contribute to the increased oral health problems seen in cannabis users? Would microbiome changes reverse with cannabis cessation? Do the same patterns appear in recreational cannabis users without CUD?

Common questions

Does cannabis use change mouth bacteria?

In this study, young adults with cannabis use disorder had fewer types of bacteria and different bacterial communities in their saliva compared to those with other substance use disorders. Heavier use was linked to more anaerobic bacteria.

Why does the oral microbiome matter for cannabis users?

The oral microbiome affects dental health, cardiovascular risk, and systemic inflammation. The shift toward anaerobic bacteria seen in heavy cannabis users resembles patterns in periodontal disease, suggesting a potential pathway to broader health effects.

Read the original research

Oral microbial profiles in young adults with cannabis use disorder.

Drug and alcohol dependence, 275, 112822

View on PubMed ↗Publisher’s paper ↗

Citation

Browning, Brittney D; Tomko, Rachel L; Kirkland, Anna E; Visontay, Rachel; Ferguson, Pamela L; Alekseyenko, Alexander V; Engevik, Melinda A; Mewton, Louise; Squeglia, Lindsay M. (2025). Oral microbial profiles in young adults with cannabis use disorder.. Drug and alcohol dependence, 275, 112822. https://doi.org/10.1016/j.drugalcdep.2025.112822