The Gut Microbiota in Addiction Biology: A Systematic Review of Substance-Induced Dysbiosis and Gut-Brain Axis Alterations.
Level 5 - mechanism / opinion, no new human data
Systematic review synthesizing predominantly preclinical animal experiments and heterogeneous observational data
PubMed 42506336 · doi:10.3390/medsci14030367
What was done
A systematic review following PRISMA 2020 guidelines searched databases (PubMed, Web of Science, ProQuest, and others) for studies published from 2019 to 2025 assessing chronic substance exposure (alcohol, nicotine, opioids, cocaine, methamphetamine) and gut microbiota composition and function. From 91,421 initial records, 60 studies met inclusion criteria for qualitative synthesis.
What was found
The abstract reports no numerical values, confidence intervals, or quantitative effect sizes. Qualitatively, chronic substance exposure depleted short-chain fatty acid-producing bacteria (including Lactobacillus, Akkermansia, and Faecalibacterium) and enriched opportunistic pathogens (such as Escherichia-Shigella). Alcohol consistently decreased microbial richness and diversity. Reported mechanisms included impaired gut barrier integrity, elevated lipopolysaccharide translocation, systemic inflammation, and substance-specific metabolic changes (e.g., glutamate pathway alterations with cocaine, trimethylamine N-oxide precursors with methamphetamine). Preclinical fecal microbiota transplantation and germ-free models suggested these shifts modulate reward sensitivity and neuroplasticity.
Why it matters
It organizes shared and substance-specific microbial alterations across five major drug classes, mapping potential gut-brain axis pathways involved in substance use biology.
Limits
No quantitative data or meta-analytic pooling are provided in the abstract. Mechanistic insights into reward sensitivity rely substantially on preclinical animal models. Human study participant counts, study designs, substance dosages, and confounding factors across the 60 included papers are not reported in the abstract.
Cited by
- supports Consuming alcohol disrupts and negatively alters the gut microbiome.